I got one of those mini-ITX motherboards running FreeBSD 4.6-Release.
The video shows up as: <Trident model 8500 VGA-compatible display device> Seems to work ok with XFree86 4.2.0
Don't know about switching to TV-out though - but did notice that it detects at boot-time if something is plugged into the composite-video output, and uses that (at least in text mode - don't know what would happen if you ran X)
Ethernet is: <VIA VT6102 Rhine II 10/100BaseTX> I've been having some trouble with that hanging on large samba uploads, but I think it's more of a driver problem (been fooling with it and getting better results)
Audio is: <VIA VT82C686A>, and got that working on FreeBSD too (listened to music with XMMS).
Got something plugged into the USB; works fine. Overall it seems to be a regular computer - just small, cheap, and quiet.