If you did it right, you could also run full/hard doors too, and make them interchangeable. This would make a really nice 'spot' to store your doors, for a day of wheelin'.
I actually looked into this for quite a while... There are a few problems you would have to deal with. The first is that the doors themselves are about 41" high. This wouldn't leave much room above/below on a 48" sheet of plywood. Don't forget to take into account how the floor and ceiling attach to the outside plywood... You'ld probably need to make the trailer profile larger than 48", which means more $$$ (plywood) and more 'complication'.
The second problem (with a TJ for sure) is that the doors actually aren't flat... They angle inward an inch or so from where the window starts to the top edge. So in order to get the door to seal, your trailer would have to go straight up and down for the lower portion, than angle inward (half-way up the wall). Again, this could be done, just with more complication.
The third (4th, 5th, etc) problem is the lack of locks on full soft doors... Than there's the thickness of full or half doors (takes-up valuable inside space)... Or the fact that you don't really have a good 'camping-style' window in any of the Jeep doors (do you want people to see inside while you're sleeping?)... The complicated shape... All of these problems can be overcome, but at what price? And is it REALLY going to LOOK as COOL as you (or I) think, when it's all said and done???
For me, it would be much simpler to just build some normal teardrop doors and bypass the Jeep door idea. I still may try a Jeep-ish shaped door to keep the look, but I've pretty much thrown-out the idea of using actual Jeep doors.
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Now....
Jeep door 'hinges'... rims and tires... fender flares... tail lights... maybe even a vinyl top could all be incorporated rather nicely.
