@ Softhead:
How should guilds chip in? Do you mean there to be a station in the guild halls to do this? What do you mean by "re make stuff"?

@ Dmatter:
- As stated, projects can be "abandoned". Yes, you only have one slot at a time (except if you buy additional room from OOO), but you can always scrap the print and make something new.
- The high costs are to encourage working on the rooms. You won't start making a room for and then say "Meh, that's expensive, I'll just make it smaller." If you pay for it, you want that room to count. The costs are meant to prevent what you are asking for: Newbs spamming rooms. It's a form of quality control.

Aaaaah.... Maybe. I don't know if that would work, but I think it could be managable, even through it wouldn't look like with designing your guild.

@Klipnik
Given that you would need to create the floor and move up to hundred objects you could not do it with the Guildhall designer. You'd need something that looks like what I made up there. Only the concept of course, but none the less. It has to offer the freedom of actually creating, rather than adding interior to a room. Think about it, you'd have to "plant" monsters, choose which tiles activate them, keep track of where what is, build walls, hide monsters beneath blocks... etc. I'd prefer it ingame, but if all else fails, it can be out of game.

Only rooms are planned to be manageable in this idea. BUT that doesn't mean, that it's not possible to design whole levels with this, as a simple extension could suffice:
Instead of just giving players one room to make, there could be up to ten or 20, which then again could be linked like in a puzzle and submitted as a whole level.

As the question fpr guild involvement had turned up rather often, I came up with a little something that might make you happy:
Guildhall exclusive LEVEL-Editor.
But first things first
Q: Why does it have to be guildhall exclusive?
A: No knight can carry enough rooms to build an entire level, through it should be possible given the size of those rooms. However, not everyone will buy the slot-expansions, so we'll assume we're talking one room per knight.

The idea here would be pooling the rooms of all the knights into one selection screen, dividing them by theme.

Q: Why a level editor and not the same room creator as in Emberlight?
A: Because it wouldn't fit with the story. The Gremlins in Emberlight and Haven are tricking you, and it would not make sense to have a double-agent in your ranks. After all, if you keep him in your Guildhall you'd "get to know him as a person". He'd spent time with you and has access to everything in your Guildhall. You'd either notice his trickery or he'd have other things to do than "selling you maps".

Q: Then what is your idea?
A: Good that you ask! Something we really should have had sooner - a arcade questline.
First of, we need a Gremlin we can trust, so where do we look? Emberlight. To be more accurate, in a good distance to the "Mapseller", as he doesn't want to be associated with him. He'd tell you, that you are actually financing the maps you are looking at, and ask, if you'd continue to do so, even while knowing that. Upon telling him, that this knowledge is important, he'll ask you to solve certain puzzles to prove that you actually know what you are talking about. These puzzles would involve the clockworks rooms and probably be based around activating switches in a certain pattern. For example the FSC room in the armory with the four stone statues: "In the depth of hell save the four knights, first the one in the south-east, then the one in the north-west, the one in the south-west and the one in the north-east last." Meaning to first put the one on the switch in the bottom right corner, the the top left... and so on.
After having done a few of them he'll ask you to, I don't know, save his child that got lost in the clockworks? Something like that, where his child can spawn anywhere except on boss lanes (like the entire FSC) and had to be carried to the elevator. The trick to this would be, that he only appears when you are in a group with at least one guildmember.
Maybe you can throw in a few more quests to gain his trust, what do I know.

Q: Great, so I help a hobo, what does that help?
A: Turns out, he's a retired spy of Tinkinzar. Which is exactly what he can do for you, getting in there and messing stuff up. Which means, "offering you the possibility to arrange the maps to be more favorable. Nothing big, but you look like you'll need all the help you can get."
He gives you a little something to show that you actually gained his trust, upon which you'd be able to interact with him in the guildhall. Getting him into the guildhall would also be a perk of the bijou, as only those that have the permit can buy him a room for his operations into the guildhall, similar to the trainingroom. This room would only be possible to enter by those with the permit, as already said. Inside you'll find...
... Nothing! It will be pretty much a big and empty room with a bulky console on the other end, as well as a chunky maschine next to it. You could call it a room-dispenser. The room would be empty, so you could place the room-plates on the ground, spin them, carry them, just like with the Design mode, only that it would be active all the time in there.

Q: Wow, that's wicked awesome!
A: That's not a question, but thanks.

Q: So how are the implemented?
A: This is the one thing I still am undecided on. Personally I'd like it to be an addition to the plans in Haven, as it would make the most sense. However should they be more expensive, or not? I tend to a "no" as it would be quite enough if financed through minerals.

Q: How many levels can a guild create?
A: 1 level for every 10 members.

Q: Anything else to be mentioned?
A: YES!
I forgot one very important aspect to the creation of whole maps: Secret passages!
Sure, you can make a switch somewhere in a room and have ot open something in the same room, but the coolest things are those where you have no idea what they do until you stumple upon it five rooms later. So, how should this be handled? Make an entire Room-editor to be accessed from the Room Merger, so you can do so fine tuning?
NO.
Colours! And empty switches! And gates without switches! Monster groups without activation! Ok, I can see how that doesn't make sense to anyone but me. so here it goes:
In each room there can be 1 switch and/or gate without affiliation in the room. Those will be referred to as "empty" from now on, because they don't do anything. Don't argue, I am the thing-namer here. Ok, now we have a room with an empty gate and one with an empty switch. We place them on the maparea in the Room merger and can then access another part of the console at the end of the room, where all the places rooms will be displayed on the big-butt screen above it. There you can change the affiliation of the rooms if they have such switches by changing their colour on the screen, so they would be visible to everyone else in the room. This would over an actual use for a screen in this game and offer the ability to create incredibly complex maps with labyrinth-charakter.
Imagine this:
You enter a room, beat to groups of monsters, but the gate on your left does not open. You advance to rooms, find a switch that doesn't open anything you see. You advance and hit a dead End. You remember "Ah, the gate back there!" You go back and the room is filled to the brim with monsters - but the gate is open. TADA!
Goodness, just the thought makes me feel all tingly.

Thanks (not a push at all).

I can't deny that it will be work, but it would be worth it. Regarding them using a GH Design Mode for this would pose difficult however, as it would be nearly impossible to incorporate such a thing into the story.

...HAHAHAHA, as if they'd care, it would probably be some Deus ex to justify that. Yeah... let's hope they don't do that.

Anyways, I've added a little paragraph to the Room Merger. I like that name, I'll use that as a titel. The paragraph starts after the bold "YES!".

I already mentioned the One-Room-Policy in the first posts addition 21.02.:
"- Potential rooms get a "special list", i.e. if there has been invested more then 250.000 Crowns it will be "featured". "Featured" rooms would not take up the Players Blueprint space, so he can go on to design a new one."
As well as in the second post:
"Q: What if you created a room, don't like it, and want to start making another one?
A: Projects can be "abandoned". Yes, you only have one slot at a time (except if you buy additional room from OOO), but you can always scrap the print and make something new."
In short: You can "hold" one room at a time, but generally you can make as many as you like and can afford - only that you have to either make one that gets featured or that you have to scrap it and start over.

The Donation-System was in the original post under "how a room is "chosen"" and "But how will others test and donate?":
However, this way everyone can help finance a room which eventually will hit the 1 Mil, after which it will be suggested to OOO. The they can decide if it is against any of the guidelines (penis-shaped, money grabbing or whatever) and then put it in the curriculum.
The 1 Million is to prevent them from having to judge more than 1 room a week. We know they need their time.

I hope this helped you guys. Also, added a "Why only one room?" Q&A to the FAQ:
Q: Why do you want to restrict players to a single room?
A: There are various reason. First, they are still cheap. While the cost may look high, they are still more than manageable for most of the veterans, at which this content is aimed. It wouldn't be to much a problem to make more than one in a short time - which leads us to second, there being far to many players for the small team of OOO to handle. Let's say 500 people make 1 room, which I find more than believable, that makes 500 rooms that can be tested, viewed, donated - and have to be saved somewhere. So let's say everyone can make 5 rooms if they want. That would be 2500 rooms that need to be saved somewhere. That you would have to browse through. Imagine it. 2500 rooms, if only 500 people decide to make some. Even with 3 rooms there would be far, far to many when every player makes one. As I am writing this I am even thinking of suggesting an even higher creation cost for tiles and monsters, realizing how vast the number of created rooms could become.

I'd appreciate more feedback on this last one, so please everyone share your thoughts on this (without starting something entirely new).

And yes Klipik, you are right when saying that it holds no personal benefit to have ones stage/room implemented, but it IS a rather costy business, so there's always the fear of having "wasted" resources on a stage. Also one has to consider that this might lead to people featuring their own stages, i.e. building a room and donating until it is featured, so they are on the save side with it. Sure there would be a way working around it, but for that I'd really have to know first how much people lean towards this whole "expiration date" thing.

Given Demons and Gremlins working together at some points, it should be possible to have those two work together. After all, Gremlins still created most of the planet by restructuring parts from other planets - I'd guess Tinkinzar bought a few of his arenas from the gremlins.