So here's a possible(?) scenario:

With the expiration of the Big 12's GOR imminent, Oklahoma arranges to join the SEC with OSU in tow. With its conference's power status in question, Texas at last bolts for the Pac, bringing along Tech, TCU, and wild card Houston.

Dollar signs in their eyes, both the Pac-16 and SEC lobby the NCAA to permit a 2-round, 4-team playoff for conferences with 16 football schools. The Big Ten is opposed to this idea due to the lack of what they would consider suitable expansion candidates. However, the ACC supports the lobbying effort, seeing it as a means to secure the Irish as full members. With 3 of the 4 remaining power conferences pushing against them, the NCAA relents.

Its hand forced, the Big Ten scores a surprise coup by poaching Missouri from the SEC. Kansas also joins to make 16. (Iowa State is very disappointed.)

The SEC is chagrined at the defection but privately relieved to have Missouri off their hands. An extremely lucky West Virginia is selected as a replacement, allowing the SEC further inroads into Big Ten territory.

As expected, ND wisely goes all in with the ACC, which picks up Cincinnati to round out its membership to 16.

Plausible? Comments appreciated!