Assuming all the speculation about the Big 12 going down is correct, I expect a new confernce will be formed by those out in the cold. It may be more of a "basketball" conference with football teams(akin to the old ACC). Or, maybe, they'll join the WAC or MWC despite not being a good geographic fit(like LA Tech belongs). And, of course, all this depends on what the BCS committee does. If they replace the Big 12, another conference is going to be quite marketable.
In another scenario, if the P10, B10 and SEC all go to 16 team superconferences, the ACC/Big East may suffer the same fate as the B12. It's possible that they'll form a mega-hoops conference and let the football teams form smaller conferences. There's no rule that says basketball and football teams have to be in the same conference.