The only ones I see in Airstreams these days are the Atwood models. Bowen used to make them for Airstream too, but Atwood bought Bowen.
The 6-gallon one should be a good fit in your trailer. Then, you will need to decide if you get one that you can turn on from inside the trailer from a switch, or one that requires you to go outside, open the hatch, and light the pilot.
The manual pilot light one is, of course, substantially cheaper and simpler (no board containing the more advanced circuitry of the remote start one), and that's what I bought a year ago to replace our leaky one.
If I were to do it again today I would get the remote start one though...