How would YOU monetize Spiral Knights?

Introduction
If it is the case that the Radiant Crystals ARE for making money, then a way around selling them as a main source of profit would be needed. The old energy system was quite ingenious, but gave a bad vibe to newer players, and arguably (but only arguably in a different thread, safe from derailment :P) had to be replaced for the game to improve. The current system minus the radiant drought is equally appealing, but seems to have mis-fired in the slightest.. if the radiants ARE for making money then the newer system wasn't performing well.
We would need a way to do this that would be both equitable to players, and profitable for the developers more profit equals more development, which in turn equals "add weapon at Spiral Knights", but faster. If we get this, then the game will have much better odds at being a "great game" someday, which is what I would hope we're all aiming towards. If Spiral Knights does work out this way, it would grant it more development time from OOO and Sega, allowing for bug fixes and optimization at a faster rate... eventually becoming smoother running, more polished, and better played in terms of artistic development (i.e. No more light blue devilites on light blue snow with light blue grievers dropping light blue mist).
The other side of this issue, which I think deserves another thread would be how to sell Spiral Knights to newer players. But I'll save that for another day <3.
Plausible Options Suggested by Myself and Others Below
These are the ways that I myself have observed and thought of. Feel free to share other ideas- thats the point of having this! Also consider that this isn't set in stone, a melding of these and other ideas might just likely outperform any specifics. I'll update this and other sections later.
===Costume Store: Selling Fashion in Any Fashion===
I think that the costume items being sold in the supply depot requires a larger player base to work. More players = more buyers and it all snowballs. Thats how Team Fortress did it- they built a strong community, and then monetized it. The other part to this is that it requires a steady flow of items with interesting models to work, taking up resources. Other games being Team Fortress 2 have utilized the community for this, giving them some of the profit on the items they make as if they are employees- furthering positive vibes about the game.
This would take a lot of time to set up, though further partnership with Valve could speed up the process, but exclude players coming from other community. An in game editor would take a huge amount of time to develop.
(Sweet-Hope) A redux of the prize box system could help sales of in game items quite a bit- where prize boxes have unique items that will never be sold in the supply depot, and the supply depot has interesting items of its own. Stratifying boxes (e.g. "onyx prize box: Heavy maid headband, volcanic dragon wings, super-prismatic halo...") See: http://forums.spiralknights.com/en/node/95492#comment-854900
(Sereos) And some random ideas for the "special rare item" could be some otherwise unobtainable things like a black/white personal color, Extra Short/ Extra Tall Height Modifier, shiny re-skins of 5* weapons/armor, special character badges or how about a "kill counter" that you can add to weapons.
I myself do like the idea of a shiny re-skin of 5* weapons... but what if it was an item called "weapon sheen", and it was applied to weapons to give them a particle effect and make them sparkle? Auras for weapons would be nice, in fact, quite a few people in quite a few threads have asked for weapon and shield customization to go with the costumes. This alone could easily be the greatest new thing for a while.
(Sereos) Moving certain items that Vatel sells to the supply depot would be necessary- things like eyes, colour mods, and height mods are out of place bend sold for crowns and would better be sold for energy. See: http://forums.spiralknights.com/en/node/95492#comment-855281
===Selling Gear/Progress Fairly in Some Way===
The original intention of the energy system was to limit the ratio of paying and non-paying members to a ratio. It relied off of players that cared for the game deeply enough to have faith in the energy system and pull through, buying and selling energy on a regular basis.
Something like this *could* be attained, but would have to be done in a way that made it seem fair to the players. In my eyes it would need to avoid giving a massive edge to a minority of players to work.. things like unique variants allow for this to work well for to this end (with the exception of lockdown, UVs are relatively unnecessary). Things like buying and heating weapons do not, though the upgraded system of buying weapons was far more fair and lenient, while still holding true to the model of selling players content. I think this model is vaguely acceptable, as long as it isn't entirely needed to progress- which raises the issue of players not buying into it at all and the game not profiting from it.
(Sir-Didymus) "Introduce more expansion missions, but make them available to all players for a small fee. An example which should not take much work would be an adapted Royal Jelly Palace with a shock theme. Adjust the difficulty to be between T3 and shadow lair. Create a new type of box which drops an orbs of alchemy or 3 radiants to place at the core room post mission, and make the mission playable only once per day. It would provide a way for players who pay to receive a few radiant per day, but not be able to be farmed."
This idea could be utilized, though it'd be nice if they just you know... made the shadow lairs into expansion missions? This would also make them seem far more just, and would likely get a lot more energy per player, if they cost the same as OCH.
(Katherine-Dragon) Hey, you forgot DLC!- http://forums.spiralknights.com/en/node/95492#comment-856142
Additional DLC would be another good way to go, though there is always the concern (or at least there was last time) that the game needs more free content for the veterans, whom have already paid to just join the community of veterans and are continuing to pay. If additional DLC IS added, I think the shadow lairs would be the best candidates. Another OCH type thing- that is, actual new content- would be plausible though I believe a new model is needed for this.
===Premium Accounts and Various Passes===
The idea with these is that you buy some sort of pass that would grant you a number of things. I would suggest offering this pass, or these passes separately, for energy or even crowns as well as actual currency- this would allow an easy avenue for F2P players to get the items, and would make the game seem more justified in having them there. This pass could:
(Kathrine-Dragon) Allow players more control over the levels. See http://forums.spiralknights.com/en/node/95492#comment-854901
Another idea for implementation of this can be found here: http://forums.spiralknights.com/en/node/95492#comment-854954
(Hyper-Galactic) Shadow lair pass (would be hard to do justly, as Hollows points out), monthly coin doubler, and best of all- access to sent mail. See http://forums.spiralknights.com/en/node/95492#comment-854925
The idea of selling extra friend slots or access to sent mail for some CE price does seem promising... just like trinket slots. You could do any number of these kinds of "passes" or abilities, and then charge a small amount for them. Improved auction house? The only draw to these kinds of things would be that it'd make the game come across as being incredibly greedy if every single feature was locked behind some wall that could be paid for in one month, and that I really can't see many people paying a monthly fee to unlock their mail sent folder.
My suggestion? Give the features to all accounts that buy any energy. The reasoning being that its a foot in the door- once people buy something once they're far far more likely to do it again- something far more valuable than a simple CE sink that would turn just as many players away.
But like Ardent-Light said, we don't want to make the game seem too much in the way of favoring the P2Pers. Allow F2P players to buy these features and make their account "paid" for a sum of energy- like 2,000 or so.
(Ardent-Light) A way to skip levels for energy would be another idea- here detailed to cost more per stratum, though I'm not certain if that or a set price of 50 CE would be better. See- http://forums.spiralknights.com/en/node/95492#comment-854954
===The Kickstarter Method - Charging for Future Content and Rewarding Direction. (my vote, if any)===
Kickstarter often has certain prizes for high paying individuals. OOO could also do this- with each energy purchase players make, they'd get a vote towards what new content, costumes, and confetti would come out. OOO would give us their agenda, and would work towards whatever goals were reached. The goal would be set according to the forecasted profits, and would explain that OOO is a small subsidiary of Sega with a relatively small dev team. The goal would be to help them expand their arsenal of programmers, developers and artists, as well as to create content that the players want.
Things that are vital to the game or supported largely by F2P players but might not garner support would still be created alongside the P2P chosen content, but would offer less direction on the part of the players. F2P players could also use their minerals (or a new pure mineral of some sort) to vote on new content, and P2P players could be given minerals to use as votes.
If I'm a P2P player and I don't like any of the options, I'd likely choose to vote for confetti or costumes instead. If everyone votes for "more swords!" then the game will get more swords, and it will be taken off the menu for a while, until the game is made to be more balanced towards the other weapon classes.
OOO could also have players pay for earlier releases- say they had put off the gunner update till February. It'd still be done around January, but they wouldn't release it immediately and would develop other content... so that the game wouldn't be slowed. No, they wouldn't say "HOSTAGE SITUATION! NO GUNNER UPDATE! PAY UP!", just "We'll work faster if money is gathered faster = better development." This would further incentivize players to work wight he developers rather than against them.
U-77654 brings up a good point at the end of his post, that steam users who buy keys would be disinclined to do so if there were a voting system.
Rating offers exactly why I wrote this section in another thread, and I think its important to keep this sort of logic in mind... we aren't just buying into some system, we're supporting OOO- http://forums.spiralknights.com/en/node/95577#comment-855751
===(Sir-Didymus) Expand into Other Markets===
"Enable unbound items to be sold on the steam community market as an additional revenue stream."
The players- at least the steam players- want this. If your product is good enough, that is, comes across as being just to players, this alone will draw in a larger community. Like with the iron costumes, steam users forced to make an account and merchant their items in Spiral Knights might just get stuck playing Spiral Knights.
But lets say that Kongregate has a system similar to the steam-market-- this should be used too. All systems that Spiral Knights can be expanded into should be utilized.

An effective, already demonstrated means of encouraging players to charge money for CE is to reward them with prize boxes. Wealthy players love rare accessories and don't hesitate to try and nab new rare and cool tails, auras, and wings.
If prize boxes were always rewarded for CE charging, through some rotation cycle, I don't see how there would be any shortage of CE purchases at all.
Adding pet costumes/accessory prize boxes will also easily encourage CE charging.

i always though if a system like TF2 could work since well you know, the accesory market its a mess now (i mean with the rare ones).
maybe something like:
lockbox could have a series which series will determine the kind of accesories they contain (and with this I MEAN THE LIST OF ACCESORIES SUCH LOCKBOX CONTAIN I DONT MEAN THAT OH WITH THIS BOX 100% SURE YOU WILL GET THIS) and well since they like to put those accesories in SD, they can keep selling them there (and soul bound to the player) for example:
Lockbox 01 series.
blablabla (replace blablabla with actual lockbox description)
"this box contain one of the following items: maidheadband, flower, toupee, mohawk, spike mohawk, or a special rare item!"
How will work then? Supply Depot will have accesories for sale there (and with this i mean the ones you get from lockboxes and soul bound to player) they will have a fixed price like they did on Flash Sales (the most pretty accesory the most expensive will be) and let lockbox contain rare version of them, for example on supply probably you can get a prismatic flower, but on a lockbox you will have a chance get the same accesory from it. but also you have a chance to get a "rare" Sparkling Prismatic Flower" which could be different from the one in Supply depot because this Sparkling flower have a sparkle effect.
this will apply for every variant of accesory, with added rare effects. Also, since we have reskinned weapon why not let "lockboxes" also not only cointain accesories and their rare variants, why not rare weapon skins?
and if we want extend this to Promos, Promos can stay the same, you can get your accesories from prize boxes you purchase in Supply Depot, so they can stay as "unique accesories" but also why not add a rare variant of the prize box? lets say there "surge promo again" get your prizebox on the supply deplot bla bla bla, people buy them from there, there a player playing arcada, vana, whatever you want, and he get "High shocking surge lockbox" which can contain a rarer accesories version from the normal prize box of the promo, and of course you can sell "high shocking key" to open them. and see? you have more ways to milk your promos.
with rare accesories that stand out more than the one you get in supply depot, and rare skins of weapons and shields, for sure i would be openning lockboxes. at least i think that could work. and let know people what kind of accesories the box contain that will be a good incentive for them to try their luck. players who wish an accesory they can buy it on Supply Depot, Elitist or players that want to stand out more than those guys who bought their accesories in SD can try their luck getting the rare version of them or buying them fron another lucky player, and the player out of luck can recover some of the key value since now accesories have fixed price in SD. also this mean something: more energy in the market.
About paying players letting them vote on what kind of content they would like to see next eh... im not sure, its not like that its a bad idea, in fact i like that since well i paid i have the right to vote on what i would like to see next. but i honestly doubt they would take care on that, i mean everytime i just log on and not play something i get that survey of "if i got fun with the game" and i just always vote "i got bored" in the game and honestly i doubt that could have some kind of influence. but anyway i would like to vote what kind of content i would like to see.
good post as always Fehzor.

I don't necessarily believe that the Radiant drought is there for money. If I were to guess, most players spend more money on CE than on Radiants. (We're gonna get this thread graveyarded because it's a Radiant discussion at any rate.) My guess is this is a sort of precursor to the new T3 boss, which will lend access to more Radiants. Dumping all the Radiants in FSC would make the new boss just about obsolete unless the new boss were some megafarm which would upset even more players.
But let's assume you're right for the sake of this thread. First option of all is more DLC. That's fairly obvious. (I did hear a spoiler about a Seerus model in the files but it's rumor.) Second would be an elevator pass equivalent because ele passes were the thing back in the day if you know what I'm talking about. So what would be an ele pass equivalent? An ele pass was basically freedom. You bought the right to go anywhere at any time and not have to pay a single mist. Since the arcade revival, this idea is viable: if the party leader has an arcade pass he can select which level to do. As in, if there are 3 levels rotating at the next depth, the party leader which of the three he wants to do. Of course there's also the discussion as to whether he can select at graveyard/TV depths but that's a side discussion. Alternatively, and perhaps more radically, a pass could allow someone to start a gate at any level. I think I'll leave it at that.

@Iron-Dragon-Guild
If you're not interested in discussing this, don't post. I'm sorry that I fleshed out the OP, but I feel like we don't accomplish much in our usual discussions. In the past, threads have had no direction to them, and have gone nowhere which causes people to feel the need to post outside of them when their points are not heard on page 3 of 7.
I do have an idea on how to fix this issue.
@Momofuku
That is true, yes. But we need a much bigger cash cow, or at least more reasons to buy into Spiral Knights. Constant promotions as the only means of getting anywhere has proven to be relatively unsuccessful in the past- demand quickly filters out, and the players begin to demand "real content". Like I said, allowing players to make costumes could be a big part in this.
@Kathrine-Dragon
No, I would like this to keep away from the subject of Radiants, as I mentioned in the OP. I just bring it up because its part of the motivation for writing this, and is what got me thinking about it. I'll add your idea to the OP.
@Sweet Hope
Thanks! I'll add you to the OP too, diversifying boxes would certainly be a more than decent idea.

I would argue otherwise though--the degree of cash charging spiked immensely from the Supply Depot flash sales and CE prices averaged almost 9k crown during that time. I had difficulty converting crown to CE since everyone was hoarding CE in preparation of each new item to show up on the depot.
Demand quickly filters out for promotions of items that are lacking in rarity or are not as appealing (ie. battle chef promotion, which included costumes of equal rarity for the most part plus a non-popular aura). More focus on releasing better looking or more versatile accessories (eye patch anyone?) will alone increase demand.
It cannot be a coincidence that they removed elevator energy requirements at the same time they began pushing major supply depot sales/accessory re-releases--they already know the huge demand that exists for people who want Hacked Auras and Prismatic Everything and people willingly cash out for those items. This model works!
Free to play model works best when the requirements to play optimally don't require paying real money. You want to remove reasons people have for saying people do better in the game because they paid money for it. While you can trade CE for shortcuts (ie. weapons from supply depot) it is universally understood that it is cheaper to earn it by crafting it manually. By focusing on accessories as the primary "cash funneled" option, the only real complaint you can make is that another player paid to look better, but in no means has any gameplay/mechanic advantage over another.
I know you didn't want to talk about Radiants, but there's a reason why radiants are a sore topic--what used to be free (heating weapons) became something you had to gather in large quantities (which was tolerable) to now painfully rare, and the remaining option is to pay an unfair amount of currency for minimal benefit to get something that used to be free. Players that are okay with this simply found other things to do (ie. heat 4* equips) but it is only a matter of time before they make the 5* jump and feel the pain--especially when 5* gear is outperformed by max level 4* gear until you hit level 7 or so.
That said, I do like the poll option: they could have 3 possibilities for upcoming events without spoiling too much and each purchase of some cutoff allows you to vote on what comes next.
For example, choices could include "Promotion Box," "Danger Mission Promotion," or "Supply Depot Sale - [item]" which could be voted on by paying players, one vote per $5 spent.
But they can really milk out a lot more money by expanding on accessories and costumes, still. They have yet to touch pet accessories and explore weapon costumes, both of which people will go absolutely crazy for. You know you want Drakons with flame auras and to disguise your Gran Faust as a giant pillow.

1) "premium" accounts get a mail sent folder and an unlimited limit on friends.
2) Monthly coin doubler/tripler to replace the elevator pass.
3) Make shadow lairs free with a monthly pass as well.
I'd argue against selling out rare costumes/accessories because it leaves little room for future rare items.

One issue with making Shadow Lairs free with a monthly pass. What if the rest of the party doesn't have that pass too? Do they get in free or..? If they do, then someone could make some serious money off of hosting Shadow Lair parties.

the other people wouldn't be allowed. You'd basically get a separate level lobby for pass carrying people only. That special lobby would then show up in its own party finder category if public.

It's a key that takes up a trinket slot and takes in a lot of heat (think: level 65 battle sprite leveling from purely heat) that could be used to unlock any key-required item. Make it purchaseable from the supply depot for 4000 energy, and be affected by heat amplifiers. This would give heat amplifiers a use, and still limit usage. Other keys would still be viable for quick access to shadow lairs and opening lockboxes. The high price plus long "recharge" rate would put off anyone who doesn't truly want one, but be a good way to give useless heat a use. If keys hold multiple charges, then the required heat would double each time, encouraging use.
Alternatively, the item wouldn't take up a trinket slot and just be toggled on and off at arsenal stations from the keys section.

I am not sure I would like to monetize it in the first place. And we must excersize GREAT percaution. When monetizing happens, most players find it as a bad thing. The safest way to monetize the game, is to make more things that can use up money. Might I suggest something much like Katherine's idea? How about we lower the chances of Arena's and treasure vaults, but boost their loot content up, and make them much easier?
Eg. Fezhor sees the chance of getting a Treasure Vault. She now pays 10ce to boost the chance of etting it by 6%. If she wants to boost it up more, she can use more to boost it. Also, rare drops (weapons armor trinket access, I am not sure about the rest, but I know weapons still, or used to drop from boxes.) wil drop. This ensures the chance of getting more than what you payed for, but makes players waste more CE by possibly failing.
Another suggestion. If you want to skip a level, you pay 10ce. If you want to skip 2 levels, you pay 20ce. And it keeps on doubling along with the price of price changes also on the type of difficulty you are on, and the level.
Confusing example ahead, brace yourself.
But before, a small recap on stratums and levels.
Stratum 1: level 1-4 recomended for 0* and up.
Stratum 2: level 4-8 recomended for 1* and up.
Stratum 3: level 8-13 recomended for 2* and up.
Stratum 4: level 13-16 recomended for 3* and upst
Stratum 5: level. 16- 24 recomended for 4* and up.
Stratum 6 level. 24+ recomended for 5*.
Ok.Done. Now brace yourselves. The nonsensical examples are coming.
Eg:
Strat 1: Level skip price on normal is 2. The price moves up by 2 every time you buy a skip. Skip price on advanced is 3 and moves up by 2 every time. On elite skip price on elite is 3. The price moves up by 3 every time.
Strat 2: Skip price on normal is 3. Price moves up by 2 every time. Skip price on advanced is 4. Moves up by 2. Price on elite is 4. Moves up by 3.
Strat 3: Price on normal is 4. Price moves up 2. On advanced price is 4 moves up by 3 and on elite price is 4 moves up by 4.
Strat 4: Price on normal is 5. Price moves up 2. On advanced price is 5. Moves up by 4. On elite price is 6. Moves up by 6.
Strat 5: Price on normal is 6. Price moves up by 2. On advanced price is 6. Moves up by 3. Price on elite is 7. Moves up by 4.
Strat 6: Price on normal is 7. Price moves up by 2. On advanced price is 7 moves up by 5. On elite price is 8. and moves up by
That probably made no sense but whatever.

One of the MAIN reasons I play this game, is due to the fact there is no membership. I don't like games that are largely biast to their paying players like Club Penguin. I hate that game. They only care for paying players. You can't even say what you want.

Honestly, I didn't want to give this too much thought because it reminded me of the same things that got on my nerves when I did work in games. But as far as player happiness, optional things are the best - you don't mess with the progress of everyone else in the game, but you give ways to enhance the player's ability to express themselves. Peoples' egos are great like that. That's why costume armor, despite their complete lack of functional ability is so expensive.
I mean, OCH was theoretically nice as an optional thing, but there was that huge slip up with non-steam players being unable to play it until recently, so because of that, it kind of got shot in the foot.
I do wonder what would happened if shadow lairs became expansion missions (huge one-time energy cost, owned forever, but inability for non-owners to join) instead of the expensive-energy-cost-to-try-but-allow-all-comers...

Pretty much the main reason I quit Runescape. But I still have rank 1 membership on my first community back in 2009.

but for games like that, it's completely obvious that the free part is just a trial or hook to get people into the game. They do treat their subscribers nicely though, right?

On the Radiants: Have only one crystal drop per box "dropping", and redo how many crystals are needed so it would be like this:
Lvl 1: Min= 1, Med= 2, Max= 3
Lvl 2: Min= 2, Med= 4, Max= 6
Lvl 3: Min= 3, Med= 6, Max= 9
etc. so that...
Lvl 1-10: Mid= 55, Med= 110, Max= 165
crystals for 3*, 4*, AND 5/. The new prices for the crystals would be: 15 Glowings for 20ce, 15 Shinings for 50ce, and 15 Radiants for 100ce. Keep in mind that crystals have their drops divided by three, and that they would sell in packs of 15. Glowing crystals would drop in S4, and Shinings in S5 and S6 depths shallower than D26. The Shining crystals in the first two/three S5 depths would be of a smaller (aiming for 40% but hopefully not too much/little) drop rate than current drop rates. Where Radiants would drop are D26 AND below. No Shinings would spawn in those depths. Glowings wouldn't drop outside of S4 as well. Also, eight red (or 12 green) boxes should be placed in the Core room if you came from at least Emberlight. That means spamming the FSC mission would grant none of those boxes, but you could do a gate that has FSC to get said boxes. These boxes would count as boxes below D25, so they would drop Radiants.
The recipes for 0-2* crystals along with said crystals themselves would vanish, and turning three Radiants to five Shinings would cost 200cr each time, and from three Shinings to five Glowings would cost 100cr each time. Vatel will no longer sell Dims and Cracks, nor will any boxes drop Warm crystals. There would be no way to make up from the vanishing 0-2* crystals other than some crazy way of giving 1cr for each Cracked, 2cr for Dim, and 3cr for each Warm. It would be hard, but I'm open to suggestions here. Boxes in S1-S3 would not drop more things from the loss of crystals dropping. The 0-2* gears would heat up like they did before the Forge, thus allowing knights to level up their gear whilst still in the Rescue Camp, and would give new knights in Haven time to soak up other information, such as Battle Sprites and monsters. A new forge introductory mission on rank 6-1 would explain the Forge and maybe give a few more Crystals. Also, the knight who explains forging should be in the Lab rather than the Town Square, because it would feel more appealing there.
Would this benefit new players? Yes, because they can level up gear at the Rescue Camp and early stages of Haven. Would this benefit old timers and high ranked players? Yes, because Radiants would drop an extra depth, and the boxes in the Core would give more Radiants.
Off Radiants: Earning a vote per 5$ spent seems like a good idea, and would help prevent Steam players from buying TF2 keys on the market and selling them for nearly twice the ce as OOO's deal. It would also give a more player-driven list of suggestions that doesn't require mass-mobbing on the forums--the developers' (and maaaayyyybe a few moderators') current system of item implementation.
The OP was too long, so I didn't read it.
But if I had read it, I'd probably tell the opening poster did you honestly expect much more from this?

I'm looking forward to when Spiral Knights Decides to play nice with Steam and gets involved. the Iron Promo was cool and now I'm craving SK steam cards XD
I think they should move all the usable things that Vatel sells (personal colors, eyes and heights) into the Supply Depot.
They could also add some special character badges that are sold in the Supply Depot.
Or how about they sell featured spots for the Auction House.
They could also add something like an "Ancient Chest" that has a low chance to spawn in an Arcade level (kinda like Scenario Rooms) that needs energy to be re-activated, and contains special accessories, armor, weapons or something like that. (It also would be perfect to add a new weapon/armor line that starts out as a broken or rusted sword for example)
And to add to the idea of Sweet-Hope:
That's a really good idea. It's such a good idea that all major games from Valve use this system (TF2, CS:GO and Dota 2)
But for that to work they would have to make such Lockboxes much more common.
And some random ideas for the "special rare item" could be some otherwise unobtainable things like a black/white personal color, Extra Short/ Extra Tall Height Modifier, shiny re-skins of 5* weapons/armor, special character badges or how about a "kill counter" that you can add to weapons.

Enable unbound items to be sold on the steam community market as an additional revenue stream.
Introduce more expansion missions, but make them available to all players for a small fee. An example which should not take much work would be an adapted Royal Jelly Palace with a shock theme. Adjust the difficulty to be between T3 and shadow lair. Create a new type of box which drops an orbs of alchemy or 3 radiants to place at the core room post mission, and make the mission playable only once per day. It would provide a way for players who pay to receive a few radiant per day, but not be able to be farmed.

@Hyper-Galactic: No, because then suddenly you are restricted to who you can invite. You would have to find others who also have the pass to go with you, otherwise you would have to solo it.

Thanks everyone for commenting, I'm really glad for the feedback- added a new section and am continuing to update the OP:
===Premium Accounts and Various Passes===
The idea with these is that you buy some sort of pass that would grant you a number of things. I would suggest offering this pass, or these passes separately, for energy or even crowns as well as actual currency- this would allow an easy avenue for F2P players to get the items, and would make the game seem more justified in having them there. This pass could:
(Kathrine-Dragon) Allow players more control over the levels. See http://forums.spiralknights.com/en/node/95492#comment-854901
Another idea for implementation of this can be found here: http://forums.spiralknights.com/en/node/95492#comment-854954
(Hyper-Galactic) Shadow lair pass (would be hard to do justly, as Hollows points out), monthly coin doubler, and best of all- access to sent mail. See http://forums.spiralknights.com/en/node/95492#comment-854925
The idea of selling extra friend slots or access to sent mail for some CE price does seem promising... just like trinket slots. You could do any number of these kinds of "passes" or abilities, and then charge a small amount for them. Improved auction house? The only draw to these kinds of things would be that it'd make the game come across as being incredibly greedy if every single feature was locked behind some wall that could be paid for in one month, and that I really can't see many people paying a monthly fee to unlock their mail sent folder.
My suggestion? Give the features to all accounts that buy any energy. The reasoning being that its a foot in the door- once people buy something once they're far far more likely to do it again- something far more valuable than a simple CE sink that would turn just as many players away.
But like Ardent-Light said, we don't want to make the game seem too much in the way of favoring the P2Pers. Allow F2P players to buy these features and make their account "paid" for a sum of energy- like 2,000 or so.
More on accessories and selling them
(Sereos) And some random ideas for the "special rare item" could be some otherwise unobtainable things like a black/white personal color, Extra Short/ Extra Tall Height Modifier, shiny re-skins of 5* weapons/armor, special character badges or how about a "kill counter" that you can add to weapons.
I myself do like the idea of a shiny re-skin of 5* weapons... but what if it was an item called "weapon sheen", and it was applied to weapons to give them a particle effect and make them sparkle? Auras for weapons would be nice, in fact, quite a few people in quite a few threads have asked for weapon and shield customization to go with the costumes. This alone could easily be the greatest new thing for a while.
(Sereos) Moving certain items that Vatel sells to the supply depot would be necessary- things like eyes, colour mods, and height mods are out of place bend sold for crowns and would better be sold for energy. See: http://forums.spiralknights.com/en/node/95492#comment-855281
===(Sir-Didymus) Expand into Other Markets===
"Enable unbound items to be sold on the steam community market as an additional revenue stream."
The players- at least the steam players- want this. If your product is good enough, that is, comes across as being just to players, this alone will draw in a larger community. Like with the iron costumes, steam users forced to make an account and merchant their items in Spiral Knights might just get stuck playing Spiral Knights.
But lets say that Kongregate has a system similar to the steam-market-- this should be used too. All systems that Spiral Knights can be expanded into should be utilized.

Last update to thread: http://forums.spiralknights.com/en/node/95492#comment-856136
Updated again-
(Sir-Didymus) "Introduce more expansion missions, but make them available to all players for a small fee. An example which should not take much work would be an adapted Royal Jelly Palace with a shock theme. Adjust the difficulty to be between T3 and shadow lair. Create a new type of box which drops an orbs of alchemy or 3 radiants to place at the core room post mission, and make the mission playable only once per day. It would provide a way for players who pay to receive a few radiant per day, but not be able to be farmed."
This idea could be utilized, though it'd be nice if they just you know... made the shadow lairs into expansion missions? This would also make them seem far more just, and would likely get a lot more energy per player, if they cost the same as OCH.
(Katherine-Dragon) Hey, you forgot DLC!- http://forums.spiralknights.com/en/node/95492#comment-856142
Additional DLC would be another good way to go, though there is always the concern (or at least there was last time) that the game needs more free content for the veterans, whom have already paid to just join the community of veterans and are continuing to pay. If additional DLC IS added, I think the shadow lairs would be the best candidates. Another OCH type thing- that is, actual new content- would be plausible though I believe a new model is needed for this.
------------------------------------- And was getting to DLC XD -------------------------
I'm really not too sure what to say about DLC though... the biggest issue is that it separates players with a pay wall, and makes finding parties hard. This scares people off and we really need a good solution to making it equitable- like with shadow lair passes.
My thought above was to have DLC be on par with shadow lairs. It'd be for end game players, and it wouldn't have the same design as the shadow lairs, but with the DLC system for keys+playable once a day. So like additional danger missions that cost CE.
But if you can think of a better way, I'd love to hear it. Solving this issue would be quite cool.

How would I monetize Spiral Knights? Good question. If I was the creator of Spiral Knights, I would make the game pay to play. (Pay once, not monthly bills). This type of model survives far better than free-to-play models. The reasons being is:
If it sells well, profit would allow for regular expansions of content in the game.
Much more content, armors, weapons, storyline, bosses, levels, missions etc.
The model of the game would be completely different; CE, the forge, fire crystals and other aspects of the game would have no reason to exist, probably replaced with a different currency, that you don't pay real cash for.
Upgraded servers, with less lag and more servers in places that don't have them (Oceania, Asia)
More DLC.
Single-Player mode. (Better story for single player compatibility.)
But these are not the only things, however.
There is so much more things they could do with this game if it had of been a pay once kind of deal. This could not possibly happen anymore however, if they had of done this at the start the game would be way better. The damage is irreversible. They have practically strangled their game.
Thing is though, they followed the same models with their other titles. Those games did not fare too well. I don't think they learn from mistakes.

Also, when/if we monetize the game, it'll have to be in a way that hardly anyone notices, because like you said; If radiants actually are for money, it is a very anger-fueling and annoying way to do so.

A lot of these ways could easily become very anger-fueling and annoying, the trick would be to ask the players what they think of the options provided after discussing them… of course, we on the forums can't really do that easily. The game is monetized as is, but just isn't quite there, as the latent paywall will prevent it from going anywhere. And I for one would like to see it go somewhere. That'd be cool.
Also, I apologize for the spelling/grammar issues plaguing by the OP… I wrote/edited much of this when I was very very sleepy.

I'd advertise the game, for a start. I only found out about SK through Team Fortress 2 and even then I've only seen SK advertised a handful of times. If SK was my game I'd be pretty damn proud of it and want to advertise it left right and center.
I'd scrap making Radiants the primary money-making method of the game because doing that just makes 5* equipment redundant (seeing as fully heated 4* is stronger than unheated 5*) and making 5* equipment a requirement for Champion while being unable to Heat it is a bit of a shlong move.
I can't think of anything so I'll have to agree with the current suggestions: premium content, DLC, costumes... basically anything that gives more incentive to make us want to dip into our wallet, without being forced to Pay to Progress, like Radiants.

Advertising would help, but I think that Spiral Knights needs a healthy way of monetizing itself first- one that isn't going to scare people off.
If we advertise now, we'll lose everyone that would stay around 5*. If we add the requisite costumes and donation systems and whatnot, and make 100% certain that people are OK with it, then we'll get to keep the larger playerbase and actually make some kind of progress for the game.

@Fehzor
Advertizing WOULD work. T1-2 doesn't have many grinding walls since you are given most of the orbs from missions. Going on to T3 gets harder, despite the abundant Shinings, becuase you don't get many Elite or Eternal orbs from rewards. Then comes the problem of leveling up 5* gear. But the difficulty of leveling up 5* gear is the last of an Apprentice's worries. Would the people that came from the advertisements start out 4*? No, so they won't have to worry. Except for one thing.
T1 Lockdown. You know, thr thing that everyone wants to do but nobody cares to host an event for. A T1 LD could be hosted with the following rules:
-Limit of ONE Heart Pendant, but no limit on amount of weapons
-Any UVs acceptable and any 0-1* items acceptable (rocket hammer excluded)
-No penalties/bonuses/balances for (not) heating gear
This would bring T1 LD back and encourage the new players (who may or may not have seen the advertisements) to enjoy the PvP. Maybe this would show what LD should REALLY be, not just polarisrevpolarisrevpolarisrev like T2-3.
tl;dr
dude! 500 words or less...just sayin....