Thank you! I have had a difficult time as well in finding any substantial answer. However, I did not even think to call the DMV or DOT. Thank you for doing all the thinking for me!
My friend, an owner of a Rubicon, and I were at the State Fair of Texas last night in her jeep and as we were paying for parking, an officer approached me and asked me where the doors were. I kind of chuckled and told him I did not know; I supposed they were at the house. He then began telling me that it was illegal to drive without doors and turned around and walked off. I don't ask the question because I completely doubt the word of an officer, it was just his demeanor and the fact that I see jeeps being operated on the roads quite frequently without any doors.
Once again, thank you for the brilliant idea of who to call and ask!