HI!
Rob Harvey here, from World Pro Audio, worldproaudio.com. How are you getting on with this Raindirk project? I make this offer: send me 1 module and I'll fit it with a nice , stuffed power supply pcb, get signal through the inputs to the outputs and send it back to you with power supply and info you need to get it all going. I'll put edge connectors on it labeled with inputs and outputs, power, etc, so by notes and by copying what I've done you'll be up and going with three channels in a jiffy. Fee will be about $320 plus price of power supply and edge connectors, approximately $100.
(reading through the thread, I'm not sure if you have the entire schematic. please advise)
Cheers
Rob