FWIW, last night I started on a tool to expose your PC's video files as thumbnail-toting RSS feeds to VideoCenter.
My intended use for this is to run it on my PVR so I can pick and choose PVR recordings to download/stream with transcoding them on the fly, but unlike other solutions doesn't rely on MythTV, VDR or any other particular backend. It just handles videos.
Theoretically, there's no reason it couldn't also expose RSS feeds like YouTube's through itself and, again, transcode on the fly when requested.
It's still a way off a release, but should support Windows, Linux and OS X. It'll also be usable direct from the web browser with Media Player or any random streaming mplayer front-end.
It's similar to Janne Makinen's "knots", but with a greater concentration on integration into auto-downloading and synchronisation (assuming that if Video Center doesn't do this yet, it will do soon)
No reason it'd be limited to the LAN if you have a direct Internet connection to your box, and an appropriate hole in your firewall, it'd work over the network.
I must be missing something obvious... but can't you use Orb? I have my home PC setup running Orb server and I can browse pictures and movies (which I selected to be shared) on my PC via N800 either using File Manager or Web browser... The PC does the video transcoding on the fly... This does work too over the internet, as long as router and firewall settings are correct.
I know you mentioned these RSS-feeds... which is likely the obvious thing I'm missing...
