It seems to me like my Xbox would be a great device to play back HD WMV video if I could find a program that would do this. Does anyone know if this is currently doable?

I think that's something they're working on for the next version of Xbox.

I found this software: http://www.xboxmediacenter.de/
I believe it supports WMV HD files. I haven't tested this, as I don't have an XBOX. Anyone try this or any other solution? Might want to check the avs forums..