When I set my TV to anything but 720p or 1080p it will just use 720p or 1080p and scale the resolution within those sets (resulting in blurry text and graphics). It will also not use an HD color matrix if it's not running anything from 480p, 720p, or 1080p which means I play the game on 16-bit color instead of 32-bit unless I use a standard resolution.
My HDTV is a Panasonic plasma from 2006, it doesn't really have good scaling options. As stated above it comes with a zoom feature that I use to get the game to be fullscreen but then it's fuzzy and only runs in 16-bit color. There's no way for me to unlock the HD color matrix on my TV unless I take it to a guy who can hack/unlock that setting (the setting is only available in the standard resolution modes that my TV supports). In reality my TV doesn't do 1080p officially, it can pull off 1080p but only at 16bit color, in reality it goes up to 1080i with 32-bit color (making it unacceptable for playing games since my framerate is locked below 30fps with 1080i). My guess is that when ever I do a resolution that isn't officially supported by my TV, it will just display it in 1080i resolution resulting in a picture that doesn't fit my whole screen and 16bit color.
I can play the game in fullscreen usnig zoom and 1280x768 it's just that after about an hour or 2 the eye strain due to the fuzzy graphics makes me have to give it up. It's strange cause I can run games over a decade old like jedi knight in 720p right out of the box and 95% of the games I own have this resolution, the only ones not having it are all dosbox games and thoes don't really need a 32bit color matrix (though they run at 480p which means my TV displays it just fine). I mean borderlands, oblivion, sword of the stars, galciv2, armada 2526, gratuitius space battles, fallout3, quake3, and so forth, all these games do 720p (though some I have to tinker with a ini file but it works).
Thanks for the help though.