If those 4 schools go to the Pac 12, then you have Missouri or WVU joining the SEC, and UConn and Rutgers rounding out the ACC. That leaves:
ISU
KU
KSU
Missouri or WVU
Cinci
Louisville
TCU
Baylor
USF
Add in BYU, UCF, and ECU/AF/CSU.
Not a dream scenario, but better than the Big East of the past few years. Lock in some crazy exit penalties, and make it happen.
I'm sure everything will change in another hour, but this does indeed seem to be the most likely option at this minute. PAC16, ACC16, SEC14, Big10(12), Big East-Big 12 merge to create a 10-12 team conference...Until the Big 10 and SEC continue to expand in the next few years. Even if you put in crazy exit penalties for these schools, they'll pay the $50 million in order to exit.