RDIO Scanner is AWESOME for personal and small-medium group use, not sure how well it scales, with all the audio stored in SQLIte and use of websockets (which can be a challenge to scale effectively ), so I wouldn't recommend running it publicly.
You can configure "Downstreams" in it, so I suppose it is possible to have one instance being the main ingest and have that feed multiple downstream instances for scaling.
I really like the RDIO SCANNER front end though, I wonder how much work it would be to adapt to an self-hosted OpenMHz backend (or even Broadcastify Calls, if you get listen API access)