I don't see why not, and the more channels you have the better. I don't have any modded boards to test it with. Are you guys using 5.1 output cards with mods? Last time I was doing anything with modded sound cards was back when we could only get XY out.
-chuck
Typically we are using a 48kHz 5.1/7.1 usb card based on the CM6206 IC A while back I wrote a dll called EzAudDac that can make that sound card look like a laser DAC, but if you are streaming wav-like data instead of frames the interface will be even easier.
Most are using 5.1 or 7.1 USB sound cards. How many channels are typically needed for what you are doing?
It's all about what you want to put out to your projector, typically XYRGB or more/fewer colors. We typically put out 8 channels when using a lightpipe, it has been mostly XYRGB_LR for my needs.