I wouldn't mind leaving the Big 12. The whole league is Texas' anyway. They always whine until they get their way on every single issue. I wouldn't be surprised to see the Big 12 title being played in Austin annually within the next 5 years.
We move to the Big 10, and have an east/west division with:
West- Nebraska, Iowa, Minnesota, Illinois, Northwestern, Wisconsin
East-Michigan, Ohio State, Penn State, Michigan State, Indiana, Purdue
You'd have 3 powers in each division.
As for the Big 12, they could move both Oklahomas up to the North, and invite TCU to come in to the South. That would balance out that division better anyway.
Additionally, this would enable us to schedule OU every year, as an OOC rivalry much easier.