The big question, would any AAC team leave to join the PAC at this point? That really depends on what kind of media deal a newly restructured PAC could get. I'm skeptical considering how few options the PAC had when it had 10 members.
I think those four teams I mentioned would. Maybe Tulane (which is the reigning AAC and Cotton Bowl Champion) would not, but the other three would almost certainly say yes. FWIW, I chose those four due to all four being excellent Academic schools for the Cal and Stanford crowd, plus, they are in good TV / Recruiting markets (MetroPlex, Houston, New Orleans and Tulsa) in the Central Time Zone.
Additionally, all four have an interesting football History. Tulane was once in the SEC; SMU and Rice were once in the SWC. Also, get this (CFB History Geek stuff), Tulsa has played in 2 Sugar Bowls and 1 Orange Bowl; SMU has played in 4 Cotton Bowls and 1 Rose Bowl; Rice has played in 4 Cotton Bowls, 1 Orange Bowl and 1 Sugar Bowl; Tulane has played in 2 Sugar Bowls, 1 Rose Bowl and 1 Cotton Bowl!
I just think this: 4 excellent Academic Institutions with former Major Conference ties (3/4) and New Year's Day Bowl (9 Cotton Bowls, 5 Sugar Bowls, 2 Orange Bowls and 2 Rose Bowls) History in the Central Time Zone might be better than adding San Diego State, Fresno State, Boise State and Utah State and still being stuck in a conference in the same region that imploded on them with good but lesser programs than they lost.
The Pac was NEVER going to survie as a West Coast Conference. They defintiely need to reach into the Central Time Zone at a minimum. The Pac-4 does not have much of an option at this point, but they can at least do something, and I would present this plan as a starting point if I was involved - especially with the home and home football games in each four team pod.