It's a pain, but it can be done. You have to get two appraisals on the value of the vehicle, which usually can be done by taking pictures of the bike to a couple of local motorcycle dealers, or they will tax you on the bluebook value. Then you are going to have to get title insurance, which is priced based on the value of the bike, and a special form you get at the local Texas Department of Transportation office. Call you the tax assessor-collector in the county in which you live and they'll tell you what you need. I did it once and it's time consuming and a pain. A better alternative is to find a crappy bike with a good title and use parts from both to put together one good bike.
Good luck,
Patrick