Didn't think so either and wouldn't have recommended it, but amazon has a bunch right now:
Most "widescreen" movies are 2.35:1 or 2.4:1, with the rest in between that and 1.77:1 (like 1.85:1 and 2.2:1). Disc labeling is usually irrelevant unless they list the specific aspect ratio like 2.4:1.
When a widescreen movie is in 4:3 format, either it was cropped, or in the case of the Back...
A 16:9 image displayed in fullscreen in a 16:10 aspect ratio must either be cropped or stretched. SC2 is fullscreen at your native resolution and does not use black bars, so its 16:9 image is cropped in 16:10 and 4:3.
Some of my 720p mkv's work, and some don't (audio but no picture). The ones that do work are a little jerky but watchable.
edit - Tried two 720p H264 Mp4's, picture but no audio. Also tried the new Rockplayer; it stutters on anything 720p, but imo plays SD xvid avi's smoother than the default...