The way multi-channel would work is through USB, specifically USB Audio C lass 2 (UAC2) which uses high speed mode and supports multi-channel. Your player software would see a multi-channel DAC, it's up to you to configure the player to get what you want on the correct channel.
UAC2 is NOT going to be part of the base DAC version, to do it right increases the cost and it would not fit in the packaging scheme we have come up with. So it's going to be an add on box developed at some date after the base unit is released. (note the ambiguity).
We've been working hard to maintain the Bottlehead philosophy of upgrade rather than throw away and get the new version. The idea being that the base unit can be extended in many different ways without obsoleting it. (I'm looking forward to the nixie tube display!)
John S.