UT would never go to the SEC. As in NEVER, EVER. UT prides itself on being the Stanford of the southwest. Bunch of left wing, elitist snobs. They consider the SEC to be full of redneck, low academic, cheating trash.
When the Southwest Conference broke up UT considered joining the Big 8, Big 10, or Pac 10. The SEC was completely ruled out.
There are some other reasons why I do not think that UT would ever leave the Big 12. First and foremost UT has more influence in this conference than they would in any other. Secondly the distance is a big factor. This conference allows them to conserve some on travel costs and it also allows their fans to see them in person more often. Also, they would not want to split apart from Texas a&m. In order for them to jump leagues they would have to find another conference willing to take two schools instead of just one. There are some other things as well.
TC