This 20 team conference Pod System sounds like its the route were going. Adding USC and UCLA makes no sense to the rest of the conference members geographically, so they have to be wanting more West Coast schools.
It just makes sense to add Oregon and Washington, and one other school. Stanford seems like the likely choice. After that....?
Is it Notre Dame, Kansas or a Texas school?
West
USC, UCLA, Oregon, Washington, and Stanford
West Central
Nebraska, Iowa, Minnesota, Kansas/TCU, Wisconsin
East Central
Michigan, Michigan State, Northwestern, Illinois, Purdue
East
Ohio State, Penn State, Maryland, Rutgers, Indiana
It's not geographically exact but it balances pretty well.