One thing that I would like to see as a feature is the ability to take one (or more) live feeds into the server and for the Rio Receiver to play them like web radio.
Alternatively, this could be done by turning the Rio Receiver into a device that can pick up from other streaming servers providing web radio sources.
This would tackle two requirements that people have....
a) Audio synchronisation across multiple receivers.
b) It would allow the Rio Receiver to act as a Radio
Using multicast, this feature could be extended to include the audio syncronisation of MP3 tracks across several Receivers. You could even have groups of receivers listening to different MP3 streams.