Visit some boat shows
I had a similar predicament, although I am in CT, not TX. Cats are not very common here, but that was my interest. I called a couple of the firms that specialize in Catamarans, but they didn't seem that interested. Maybe that's because I was looking for 36' or under.
I found more success at the Annapolis Boat Show. I found that a couple of brokers were willing to take the time to talk with me about my needs and about boats. I really was impressed with the Seawind 1000XL, which I look set to buy new. I really appreciated the time that Steve Marsh of Finish Line spent with me going over the boat, and just talking things through.
I would recommend going with someone who does a large share of their business in catamarans, but you also need someone who will demonstrate initiative on your behalf. They are out there, you just have to find them.