Is there a possibility that PS3 Media Server will be included as a plugin at some point? It is a DLNA-compliant UPnP Media Server written in java (is that a problem?), with Linux versions of the software. It also transcodes on the fly, so .mkv files can easily be viewed on the PS3. Although it's not limited to supporting the PS3, but also the Xbox, televisions, smartphones and so on.
The only coding I know is Python 101, so I have no idea if it would be hard to do.