If Nebraska, Missouri, Colorado all leave I think the Big 12 easily survives.
- Colorado State is an easy replacement for Colorado.
- Move Oklahoma and Oklahoma State into the North Division
- Invite TCU (which has been a top 25 team for a few years now, and a rising program, that plays great Defense)
- Invite Houston (beat 2 Big 12 Programs last year) and bring in a very explosive Offense.
If that happens the Big 12 not only survives, but becomes a little more balanced between the North and South. I still think that the South would still be a little more powerful and the additions of TCU and Houston could prove to be very formidable foes to Texas, and they would only get better, their recruiting and talent level would increase immensely as BCS schools.
Then they would decide if they want to expand to 14-16 teams. If they do, they have to target Arkansas. A lot of people say they wouldn't leave the SEC, but they would love to be playing in Texas, and get into the Texas recruiting base. If the Big 12 improved their media contracts I think Arkansas would at the very least seriously consider the move.
Other potentials are Utah, BYU, Boise State.
*If Texas, Oklahoma leave as well whether it's the Pac 10/SEC/or Independent then yeah the Big 12 is done, they look more like the Mountain West Conference than a BCS conference.