There has definitely been prior discussion of having a 30-team league. I believe the largest league at the moment is 20 teams, which was approved as an experiment of sorts (I think that ties to the thread below).
The concept of tying buy-in to projected value is interesting. You could see a league where participants pay a percentage of the highest projected value. The best way to handle that might just be having an offsite league safe on top of a basic $20 league here. The total pool could just be set to pay out a set portion of whatever funds come in for teams that win–but if handled offsite, also a bonus or something for the Oakland As of the world if they finish in the first division or something.
Lots of options, sounds interesting, even as a 12-team league.