Lean, I have used a lot of these IR repeaters from Xantech
You do have to run Coax (standard cablevision cable will do) from sound booth to the projector.
The units that convert the signal from IR to coax is smaller than a pack of cigarettes.
Cost was about $120 for 1 pair the last time I purchased..
http://www.xantech.com/Infrared/Infr...xKits/17294RP/