If I was the Pac Ten, I would choose Utah and Colorado if I could get them, which I think is a strong possibility.
Colorado made their mark recruiting out of California. They would do way better if they could tell their recruits they would be playing in LA, Berkeley, and Palo Alto, instead of Columbia, Lincoln, and Manhattan, Ks.
BYU should be in a National religious and military independents league with the likes of Notre Dame, SMU, TCU, and the service academies.
The thing to understand is that the MWC is really close to getting an automatic BCS bid due to conference performance. Accordingly, it would behoove the bigger conferences to go after a MWC juggernaut, like Utah or TCU to drop their winning percentage numbers down. So, if the Big Ten pulls from the Big Twelve, look for them to go after TCU, or Utah. While most would think TCU the likely choice, the Big Ten will be pulling from the Big Twelve North, (Nebby or Missou) which means that Utah might be the more likely choice. A Big Twelve north of Utah, Colorado, and Nebby as the top three teams looks a lot more representative of a regional group than Colorado, Missou, and Nebby.
Basically, watch BCS conference expansion raid the MWC. Also, watch Boise try to to something to save themselves. If the MWC folds, the remaining teams will try to bolt for the WAC, which will reduce the viability of that conference even further. If that happened, I would suggest that the WAC, CUSA, MAC, and Sun Belt form some kind of super conference with the a playoff structure to get the champion into the BCS.
Finally, if the Big Ten pulls Rutgers from the Big East, that league would look dangerously close to losing their BCS automatic bid. They would then have to consider some drastic moves.