Sure... I will put the entire development tree up for download and send an announcement (probably this coming weekend).
As for the DSM-520... it worked like a charm. I had it up and running in 3 minutes, plus another 20 minutes because the MythTV UPnP server (in the 2.0 version at least) doesn't seem to be too robust. I downloaded and installed twonkyvision for Linux and got that to run in a few minutes and after that I now have full access to all my media (music, pictures and video).
The UI is ok, there are some things that SDesk could do that I no longer get (like support for video cover art, video details, my home automation stuff and some of the other nifty addons). I tried divx (converted from flv), mpeg2 and mpeg4. As for music, the only format I tried is mp3. Picture quality is as good as it was with the Roku (I don't have any HD, so I can not comment on the HDMI output).