Pure dreaming on my part, just having some fun...
What if the Big 12 listened to then commissioner Kevin Weiberg and started a Big 12 Network, instead of him resigning and taking a position with the Big Ten Network?
Say the network gets created in 2008, and takes a few years to really build up, similar to how the Big Ten Network developed. Perhaps the schools even sign a GOR along with the creation of the network, and there's never any big push from the Pac-10 to expand with the Texas and Oklahoma schools. After a few years of the network stabilizing, perhaps the Big 12 looks into expansion to push the network into more areas.
With no SEC network created yet, but both the Big Ten and Big 12 having them, could the Big 12 perhaps have raided the SEC? Jerry Jones had previously pushed for Arkansas to join the Big 12, and I think with this scenario the Big 12 may have been able to grab them, and possibly LSU as well, putting the conference at 14 members. This adds 2 southern teams, so divisions would have to be changed, or perhaps the conference could expand with 2 more teams in the North as well.
BYU was a candidate for the Big 12 when it was originally formed, and they'd certainly get a look again, although the Big 12 might prefer the state run school of Utah. The choice would almost certainly be one or the other, as adding either gets full carriage throughout the state, and the second school in the same state would bring much less value. The second school in the North might be harder to get, as there is no G5 teams worthy of being escalated to P5 status in a contiguous state to the northern teams with the possible exception of Louisville. They likely wouldn't be able to raid any Big Ten teams as well, as their network would keep any schools from leaving. At that point I think the Big 12 pushes very hard to get Notre Dame to join. I doubt they'd be successful, as the Big Ten would likely also be trying to expand at that time and of course there's the huge thing about Notre Dame wanting to remain independent. It most likely comes down to either Louisville or Cincinnati, or doubling down in a western state by adding Colorado St or taking both Utah/BYU.
Potential Big 16 Conference