A few things to keep in mind, based on what Clay Travis has said over the years:
1. 4x16 probably doesn't happen unless a few ACC teams are poached by the SEC and B1G. (Possibilities include NC State/Virginia Tech to the SEC and Georgia Tech/Notre Dame to the B1G.)
2. The SEC and B1G are not interested in bringing in teams from states that are already represented in their respective conferences. They're going after new markets. (The one exception would be ND.)
3. As stated above, don't expect the Pac-12 to bring in any religion-based institutions.
4. Texas wants no part of the SEC. Probably not wild about the B1G either.
For the record, I can't stand Travis, but he knows his stuff on this particular subject.