Well... there almost is :-)
Some of you (those who read HomeToys for a start) are probably of the xAP protocol. www.xapautomation.org
xAP is a light-weight protocol to allow "home automation" devices to communicate relatively small amounts of infomration with each other.
The two pieces that need to be written are a TV display module, and a xAP broadcaster for the Rio... the TV display module is now in Beta, and runs on PIC hardware.
The xAP broadcaster for the Rio is a subject of active discussion on the xAP developers forum at the moment. Trying to work out whether it's easier to write a hack into the Rio kernel, or have JRec broadcast updates in the style of the existing JRec status panel display.
At present, the debate is JUST around the "currently playing" information, rather than attempting to recreate the interactive menus.