I didn't make it!
I found a new vehicle in ut2004's ed, but it's not finished. Was wandering if anyone has any plans to finish and add it to the game. You can summon it in instant action by typing: "summon vehicles.bulldog" It looks pretty good and you can get in it, but that's it. The Dragonfly "Bomber" would make an interesting vehicle too. Would do it myself, but I don't have the time to learn how, or the patience.
The Bulldog's been in there since UT2003, I don't think anyone ever cleaned it up though. The UT2003 version had a rocket launcher, haven't tried it in UT2004 though. Someone did however clean up the bomber and make it playable in-game. I'm a bit knackered to find a url at the moment but try googling "Dragonfly bomber mod UT2004".