Potentially new scenario for discussion purposes:
The ACC survives!! That conference is in the same place right now that the Big 12 was in July 2010. Nebraska and Colorado had left, there were rumors about others looking around. Ultimately, everyone made a statement of solidarity and we all hung together for another year.
However unlike the Big 12, the ACC doesn't have to worry about an uber-insecure fanbase causing problems. FSU fans are restless and a little unhappy with the ACC, but they don't have an inferiority complex that even comes close to what A&M had. And while UVA or GT may be preparing their backup plans in the big 10, neither of them are spreading their legs for anyone that so much as glances in their direction (Mizzou).
The ACC actually holds together without any more defections (current 11, plus Pitt, Cuse, Lville). I think the SEC will then have no choice but to stay at 14. I think the big 10 will stay at 14. I think the PAC will stay at 12. I think most members of the Big 12 would like to expand, but Texas does not and we also can't agree on how to organize the divisions, so we stay at 10. Besides, with the ACC surviving, we have no one to add anyway.
I think we have 5 major conferences competing for 4 playoff spots for a few years. Then the playoffs expand to 8 teams and everyone realizes that we don't need only 4 major conferences anymore because there's room for everybody to make the playoffs, and we all live happily ever after.