Update: We had a meeting today discussing this. The work on linux server port should start in few weeks (depending on how fast we'll be able to wrap up current tasks). The initial version should be headless (no UI) and have simple configuration file interface.
Good news. I just got the old AirVideo server up and running on my NAS4Free server (FreeBSD based), since that's where all of my media is, so it would be great to be able get it running there. Especially since I don't have a spare machine to run it on.