Ok, I am and have been a Texas GC for many many years. Here is the scoop. Yes you do need a GCs license but as someone else said they are local in nature. Usually a 25 dollar fee and 5000 bond for 50 bucks and poof you are a GC. In some areas like New Braunfels you need a credit check too. In places like San Augustine (although haven't pulled a permit there in 20 years) you just pay a fee per job in addition to the cost of the permit.
You still have to pass all inspections to get your CO. You still have to deal with the central Texas snobby (we are better than you) inspectors. You still have to learn all of the local ordinances. If you don't it will cost you more in the long run than of you hired it all out. I have seen many "GCs" from other states that were state licensed that were hacks. I am sure all of you have too. But if I do a job in many cities in Texas like I do I have to have as many licenses as there are cities.
But you can pull a homeowner permit and still be under the gun by the man. Usually these people are hammered on more by good inspectors than GCs are.