[Fka200]

These are fairly recent:

http://answers.yahoo.com/question/in...6151755AA2vvb2

http://answers.yahoo.com/question/in...0031624AACbMRc

http://forums.techarena.in/media-center-pc/1060381.htm (probably the most helpful)

http://forums.cnet.com/5208-10151_10...hreadID=278620 (2008, but some information in the comments about codecs)

http://www.videora.com/en-us/Convert...360/video.html

Some free time on my hands... not sure if those will solve the problem, but gluck. I'll call up a friend with a modded Xbox 360 and see if he knows anything just in case!