I have a project dealing with video conferencing using the Kinect (or, more likely, four of them). Right now, my company uses these stupidly expensive cameras for our VTC rooms.
Sounds interesting, maybe you need some "automatic calibration".
Maybe with some "remote power switches for each usb connection" (io card connected to the usb powerlines). So you could power-on one Kinect after the other automatically and now you know which microphone belongs to which camera.
Or something like that...
Regards! Stefan