Modifying the hitch is simple. Use a standard receiver and get a pintle-type insert. That way you can still pull stuff you have to rent with a 2" ball insert.
Try Jeepacres, (219)654-8649 in Indiana. They may not have any trailers, but may have a line on some. That's the only one I know of off the top of my head. You can search the net yourself and probably find dozens more.
Join MVPA, or at least check out some of their meets. Makes finding that sort of thing much easier.
Check with your local laws though. Oddly enough some states don't allow the pintel-type hooks for towing trailers on personal vehicles. I don't know why as it's better than a ball hitch, but whatever.
Also if it's for a civillian Jeep, you may just consider making one. If you build it wo it will take the same rims and tires, it may come in handy off road. It would also let you build in things like air-compressor, etc.
Ross