A friend of mine created such a szenario, but he also wanted to copy tv content to his media box, he used this:
http://www.techcase.de/index.php?cPa...574016c92e1ce2
This is a small all in one mainboard, VERY! quiet and needs only a small amout of power, with free software ( i think it was vlc media player ) he created his own server, the cool thing with a tv card on this board you can replace your DVD / Reciever / Recorder etc.
ok, you have to buy the hardware, but the software is free and very good.
perhaps you are looking just for this