Awesome. Really looking forward to see what you're coming up with!
But I also wonder what you will do about the sound system on linux. By default many distributions come with PulseAudio which is, well .. crap ... and that's an understatement!
Default configs are on 44/16 and resample everything (quite badly too IMO). There is no exclusive mode as far as I'm aware and many distros get in trouble if you try to adjust the default config. For instance, when I tried to edit daemon.conf (PA's config) to adjust it to 96/24 (which really, is just 2 words and restart PA), I lost my left channel. When I reverted the config file the left channel did not return.
Other annoyances I had was that apparently the option to switch outputs (from main to headphones for example) is not always available, it depended on the shell I was running (Gnome, KDE, etc). I figured it was just a missing applet and the audio layer was still able to, but from all the programs I've seen and tried on linux, none offered options which were not available to me in the OS itself. Ie, none offered 24-bit output or sample frequencies higher than what PA was set to, none offered exclusive modes and none were able to switch outputs if the OS wasn't able to.
There are some distros that seem to be able to properly output audio without resampling, but these are dedicated for that purpose. XBMC's OpenELEC is one.
Or maybe you can completely bypass PA/Alsa, probe hardware and access it directly? I don't know ... or ...
How cool would it be if you would make an appliance-like version? A Linux distro stripped to the bone and dedicated to only run JRiver Media Center, like some forks of XBMC (OpenELEC). It comes without a GUI and boots straight to the application. If you want to do anything, you need to enable SSH and remote shell into it.