At a recent show I saw fella running a digi patch bay I had never seen before. Had coax s/pdif and optical outs and ran off of a 6v SLA if I recalll correctly. Pretty cool looking unit, had an LCD that displayed the voltage left in the battery.
I spoke to the guy running it and he said it was built by a person named Neil Sturtevant. He also mentioned that it takes a very long time to have one built. Apparently Neil is just a taper that makes these upon request for other tapers. I don't have any contact info, but perhaps this may point you in the right direction...