Hmm....I suppose the Big 12, with 10 schools, could have a conference playoff but they would do better to add more schools. They’re stronger than AAC. I would suggest BYU and Memphis.
Playoff game could be at Kansas City, or maybe St. Louis now and then.
BYU would be a good addition, but Memphis?
The Big Ten is for flagship schools, not local branches.
The board of Notre Dame is gradually moving more conservative, although the hippy in Rome isn’t helping things. If the Big 12 were going to bust out of the lower Great Plains enough to add BYU, I think Notre Dame would be the (perhaps unattainable) goal.
If Notre Dame is unattainable, I think Houston would make more sense than Memphis. For now, it has a weaker basketball reputation, but it’s a far better football school. And the entire 70,000-student body of the UH system would think of it as their team.