I have just ordered a SBC Phidget and can't wait to have a play with it. I was wondering though would it be possible to get the SBC to stream an audio file over the Ethernet and then get the sound out of the SBC?
I have actually been hoping to do something like this myself, but we don't have a USB sound card here to test. The SBC has USB audio support compiled into the kernel - so it should be just a matter of compiling and installing something to receive the audio and output it - there are several projects out there which do just that.
Using an HID compliant USB sound card, with a few additional modules installed, we were able to stream an MP3 over the internet, to the SBC and play music.