i don't know about specifics, but I think that it should cost a fairly large amount of crowns and energy for the initial purchase of the feature since it would be a pretty big feature (both currencies because that will help the economy become more stable.).
-Purchase of feature 400+ce & 5k+ crowns
-designing a level 100-500 crowns
-saving a level 1k - 2k crowns
-posting a level 10ce & 3k
these are just prices that i think would be pretty fair
also maybe the prices could vary depending on level size or amount of objects inside. Or another idea, maybe have a level design catalog with all of the different monsters and objects that the guild members can use (each thing only needs to be purchased once and then everyone in the guild can use it in their levels.) although pricing would be more complicated for this.
Ok, I sort of know what you are talking about, and I guess it could be integrated into the current 'dungeon' idea we have now
( http://forums.spiralknights.com/en/node/15207#comment-94126 ) but this would have to have its own seprate update in order to accomodate all of those things. Other than that, it seems okay; except for how much it would cost to use it and such, we need to decide on that.
Also, as for that link you provided; added to my favourite bar. I'm going to look over it and see if there is anything which could possibly be integrsated into the list.