I'm glad you asked this because I'm interested as well. I thought about a pre-built unit, similar to this, but they are way over priced. So, I want to do exactly what you want while adding a Slim Devices Squeezebox or the Roku Soundbridge. I suppose there must be some type of operating system to do so though.

M60s
VP150
QS8s
Marantz SR6003
Samsung LN52B550
Oppo DV-980H
Insignia NS-WBRDVD