I think it would be a lot easier to develop a port to Wii, so you could bypass all of that red tape with xbox development. Wii has an enormous homebrew scene, and it's easy as hell to hack one for simple homebrew use. From a hypothetical standpoint though, is there a way to code a port using the Wii SDL library with just the RPG_RT.exe and resources, but without the 2k/3 source?
There's not a lot of hidden magic behind what RPG_RT.exe does and how its supposed to behave, so there's not really any reason one couldn't remake from scratch a program that does the same thing for wii.