Well I think we have a solution that is working pretty nicely. We are using Ustream to stream from an newer iPhone sitting on a tripod with a nice view of the worship space. This is done using wireless to the apple router and then out to the internet. Then, we are launching Ustream on the iPad to view the live footage with about a 10sec delay is all. We then launch Airplay on the iPad that to mirror that to the Apple TV in the other space.
Surprisingly the audio and video work nicely, with minimal delay...
Ustream is pretty cool.
ps: also works on Android