I don't know of any. I know that there are a couple in San Antonio, but none that I'm aware of further south. I've never been to the ones in SA, though, and I hear they are small.
There is a big one in Houston, and of course Austin HomeBrew in Austin, but those are the only ones I know of, and that's a very long way for you!
I don't brew when I'm in Texas, but my neighbors order from austin homebrew, or from northernbrewer.com They used to love northernbrewer's flat rate shipping, so they ordered from them even though it was so far away. Austin homebrew still has flat rate shipping (I think $7.99) and they have good quality ingredients and fast delivery, so it may not be a bad way to go.