You could try this the Macsense Homepod powered by Gloo.

Its a 802.11b wireless Ethernet +10/100Mbit/s Ethernet music playback device that can play mp3/wavs etc, comes with javavm builtin, runs Lunix [uses ARM processor I think] , has FM radio, Blue backlit graphical LCD display with (white) pixels & comes with a small IR remote.
The inbuilt USB port on the back is a USB host port [not a slave port], so you could connect external hard disks to it to play music from if needed (and or any USB devices you have drivers for) and it has optical digital out, inbuilt (tinny sounding) speakers and line out/head phone out. Front panel has 4 "soft" buttons plus rotary encoder with push function on it.

Price is $249USD for the developer version [with full java sources etc] (buy this from Gloolabs direct).

Since it fully programmable, then you can write whatever apps you want - or use whatever apps other folks have written. Seems to have a developer community.

Comes with "media server software (java based)" for Windows/Mac and Linux to allow Pcs to server up files to it.

Only problem is that the case is iPod white (only).