Hi,
in 2008 the company fon.com released the Fonera 2.0g
which is an openwrt-based wifi router (so no need to flash....add serial ports....)
Their main goal was "wifi sharing" but this device got an openwrt which allows 3rd party plugins and usb 2.0 port
one of the plugins is the "music"-plugin. : http://wiki.fon.com/wiki/Plugin_Music_Configuration
it can easily be installed using the "plugins" section in the web-gui; all sourcecode is given
http://wiki.fon.com/wiki/Plugin_Usage
and it can play music from your "usb" pendrives/discs or play from radio stations you add to it's internal database
Instead of mpc/mpd the following exists:
audiod : http://trac.fonosfera.org/fon-ng/browse ... fon/audiod
fonostream : http://trac.fonosfera.org/fon-ng/browse ... fonostream
music plugin : http://trac.fonosfera.org/fon-ng/browse ... luci-music
there is also a list of usb audio dongles that can be used : http://wiki.fon.com/wiki/Soundcard_compatibility
including cheap ones of 5$ on Ebay
At the moment they only sell a wifi-n enabled device : shop.fon.com -> fonera 2.0n