> One of my design goals is to NOT require a computer in every room, except
> maybe a laptop to access the server and tell it where to send the output.
> I'm not sure if we need to install separate sound and video cards for each
> room, or what.

You're going to need some kind of computer to get multiple independent mythtv 
outputs, there's no good/easy way around it.  You could install the frontend 
on a laptop/minicomputer and whereever you plug it in, it'll get access to 
the same backend data (video, etc) that the server has.  You'd plug the 
laptop/whatever into the video and audio in that room.  Go for something like 
a VIA epia (~300) if you want something small, cheapish, and quiet that can 
handle multimedia.  Any video you'd stream through your house wiring would 
have an extremely degraded signal, and the audio would lose some fidelity, 
and you'd have to string a big mess of wires.  

> I've only just started doing some research on this, so I haven't really
> RTFM yet. Just hoping to get a few pointers from those of you who have done
> the same or similar.

Definitely RTFM.  Mythtv is very complicated and specialized - it certainly 
finds a way to punish you if you don't understand everything the first time 
around.

-Dave