Texas still has a lot of hardwoods in the river bottoms don't they? even if they are in state parks or something you may still be able to cut one. A few years back i contacted the Minnesota Parks department, told them my story and actually got permission to cut a few trees from a park, I was going to meet a worker at the park and we would choose the trees together. It ended up getting postponed and then I was in the middle of moving so the whole project was scrapped but i was encouraged to see that they would work with me. I think people are always more open to this type of stuff then we think they'll be.
Search on craigslist for terms like: firewood, timber, logs, tree cutting, etc. I once saw someone willing to pay a hundred bucks to come "take care of" a big black walnut, unfortunately someone beat me to it.
Once you start making connections and people know you are looking for logs, they'll come find you and you'll be wondering where you are going to store all these staves!