I just picked up a Russound CAA66 6 sources 6 zones. And a selection of keypads you can use.
Alternatively you can also throw a spare desktop/server in the audio rack and run somethinglike CQC (i do this) and control the CAA66 with a RS-232 cable. You can then get their Ipad controlling app and build your own control panel for it.
If you have cat5 going to each room/zone you can also use the control pads and put them in the wall to control the source/volume.
you can pickup the CAA66 for 700-1300 on ebay.
Orrr you can go wireless.
http://www.sonos.com