Interesting topic... glad to see I'm not alone in not titling dirt bikes. I have an '06 KX250F that I'm trying to sell... I bought it in OK because I save a ton of money and no sales tax. No Texas Title is applied for in this situation. You do receive a bill of sale and the Manufacturer's Statement of Origin. When I paid the bike off I received from the finance company a letter releasing the lien and the documentation for me to be able to go apply for a Texas Title.
I'm selling it and don't plan to have it titled. I have documentation proving it's mine and that the original lien on it was paid off, but I'm not sure if that will be adequate for a lot of folks that feel a Texas title is important. Guess I'll find out eventually...