http://www.cbssports.com/collegefootball/story/12973291/texas-ad-no-talks-with-big-ten-about-expansion?tag=untagged (http://www.cbssports.com/collegefootball/story/12973291/texas-ad-no-talks-with-big-ten-about-expansion?tag=untagged)
Looks like the Big Ten will have to find someone else to join their conference. They did say that they would like the Big 12 to replace a school that leaves with another school. Who knows who this school would be if someone else from the Big 12 left? They said that they don't want a domino effect in their conference but maybe they could end up causing one in another conference.
They have not had official talks. I know that they most certainly have had unofficial ones at the highest levels.