The two spent most of their history in seperate conferences.  While I agree that they will always be rivals I could easily see them in different conferences because Oklahoma is not going to give in to whatever Texas wants to do.  They have their own ideas about what is good for the Sooners.  If that includes Texas good, but if not, oh well they'll find a way to regularly schedule them just like when OU was in the Big 8 while Texas was in the Southwest Conference.

Having said that I think the Big 12 doesn't really have to do anything.  The league is very strong right now.  It's certainly in better position than the Pac 12 currently.  While a lot of people thought the league should have expanded, they were all wrong.  A smaller more cohesive conference with round robin play was the correct play.  I don't think the superconferences thing is actually going to happen, but if it does the Big 12 should just full on merge with the Pac 12 and rule the entire west half of the US for college sports and allow West Virginia to leave if they don't want to be a part of it.  I'm sure the ACC or SEC would scoop them up at that point.