Yeah, the RME Digiface USB seems like it'd fit the bill, and then just do optical from one computer to this device. However, it's rather expensive for my case w

Yeah, the RME Digiface USB seems like it'd fit the bill, and then just do optical from one computer to this device. However, it's rather expensive for my case where I basically just want to pipe audio from one computer into another without having to lose quality. If anything, such a device should be cheaper than even the cheapest USB ADC, since it doesn't even have to do any analog stuff, just carry bits between the input of one usb class device and the output of another, I'm going to build this, because it annoys the heck out of me that such a simple device don't exist. I'm way too principled, which is how I ended up with a USB AES/EBU output device to stay digital right until the speakers does their thing :\ (which is also partly why I'm extra annoyed at having the second computers output going through that extra unneeded DAC/ADC conversion for no damn good reason!) ;)