Synergy or VNC (Score 1)

I would suggest getting an old PC and putting it under the couch, and connect it to your LAN. Use either Synergy (synergy2.sourceforge.net) or VNC to send the keyboard/mouse signals to your server. If you set it up properly, you don't need to see the under-couch box at all. You also don't need anything very powerful, and you don't need to attach a screen, beyond initial setup. $50, tops! With a slightly nicer box, this could also give you a local spot for dropping in a dvd drive (auto rip and deposit on the server, perhaps?), local USB or firewire, and anything else you might find useful on hand.