Pretty sure this game, like any other, uses standard directX resolution restrictions.
It's MS that made it tough to set custom resolutions like that, not the devs. But it is possible, it just takes some forcing. There set up to use standard resolutions and 75 or 85hz refresh rate, regardless of what is supported... But you can fix that.
First off, you have to actualy have that resolution available and working in windows, at a standard vesa complient refresh rate, ie 60hz, 75hz, 85hz, etc.
The latest ati/nvidia driver have many such resolutions pre programmed, like HDTV widescreen 720p 1280x720. Shouldn't use 768, unless that is your native rez, mostly lcd's do this, not DLP.
Then your monitor driver also has to support it. Generaly, they do not. So you have to make a custom one.. Download powerstrip, it has a function to detect EDID/DDC data, set up a driver inf and install it.
After that you may want above 60hz, to do that, get Refreshforce.. Google it, great app, run it once, it removed low refresh rates, preventing them from being used at all.
BTW Xbox actualy has built in support for HDTV 480p,720p,1080i resolutions. Not sure what the game supports, but most do 720p. So if you must have it looking nice on your TV, the xbox version may not be a bad idea. You do need the correct adapter tho.