In a pretend land where the Big XII knows what they're doing, some college presidents in the Big XII realize that the South is where college football reigns....and from this premise, they push forward with expansion, adding Houston, Tulane, Memphis, and UCF (or one of the Florida schools).
This set up would bring the lucrative and upcoming Houston market and school. It would bring New Orleans, and a great academic institute in Tulane (as well as former SEC school). It would bring one of the hot Florida teams with a large student body, great recruiting, great market and great destination. And it would bring in Memphis (and FedEx??), a great school that would loosely connect all points of the conference.
This move would be geographical in nature and create an east and west wing that overlap with Texas schools:
Big XII WEST
Oklahoma
Oklahoma State
Kansas
Kansas State
Iowa State
Texas Tech
Houston
Big XII EAST
Texas
Baylor
TCU
Memphis
West Virginia
Tulane
UCF
This would keep old Big 8 rivals together, while bringing in Houston as a prime Texas destination for Oklahoma, Kansas, and Iowa teams.
It would allow Texas a new set of competitors for the LHN, and help out West Virginia with some Eastern schools.
That said, I doubt this happens