Just bought the game, and I'm pretty annoyed to see that a game this recent doesn't have widescreen support.
Does anyone know of a mod, or hack to enable more resolutions?

Yeah the lack of widescreen would be ok if the game could be played in a window but I dont see that option.

You can usually set your video drive to scale the image, while retaining the proper aspect ratio on fullscreen, which I guess is better than nothing...

Strange, I had no issue: I have a 1920x1200 screen, and I didn't do anything special - it just automatically centered the 1600x1200 fullscreen game and blacked out the sides. Are you getting stretching?

(I'm running Win7 64-bit and have ATI graphics)

You're not often put in situations where the added horizontal viewing angle would be all that useful, although I suppose it could help when melee-dancing with vampire packs.

Yeah I can't seem to find a way to have widescreen either.

Kind of a dealbreaker for me :|

Check your monitor settings, the actual buttons on your screen - that fixed the stretching issue for me (Samsung monitor), it had all 4:3 resolutions set to stretching by default.

Is there a way to enabled a windowed mode with this game?

Here you go!