Although there are many ways to do multi channel, I am doing a combination of things. For hirez music I use the analog outs of my Oppo to an analog mulitchannel preamp, to separate dedicated Modwright and McCormack amps. For movie surround I use hdmi and a Denon receiver (as surround processor) then send the sides and rears to the receivers own amps.
I will be trying to help pioneer multichannel computer audio, and documenting it here. Things like DoP version 1.1 allow multichannel native DSD, and so I'd like to start there, with likely a Mytek 8 channel DAC or set of stereo Mytek's. The drivers need to be figured out, though.