The only events in TX I judged last year were KCBS:
Sams Club in Conroe
Sams Club in Austin
Sams Club in Fort Worth
Bedford Blues Fest.
From what we were told as judges, Sams Club is in it for the long haul so they will be back in 2012 from. Bedford, is a really awesome long running contest and well organized by the city (Wendy especially).
If you are just looking to cook, LoneStarBBQ (not KCBS affiliated as far as i know?)