I'm staying away from the ledge.
OU and TX may be shopping around, but if they go anywhere, it won't be for 5 more years because the Big 12 owns their TV revenue until then.
I also doubt OSU is going to the Pac 12 because the Oklahoma legislature has said before that OU and OSU are a package deal.
Finally, I don't think it's a given that KU would end up on the Big 10. They have the worst football program and football facilities in the country. The Big 10 is already dragged down by Rutgers, and I don't think they want to take on another program that is the laughing stock of Div I football.
I do worry, though, that this latest flirtation by OU and UT has destroyed whatever level of trust and loyalty the Big 12 had developed after the last missile crisis.