MPD runs anything that'll run *nix. Here's the proof:

• LinuxDevices About the Blackfin
• The Uclinux Branch
• UsbAudioHowto Running on OpenWRT (e.g. ASUS WL500gx with USB Audio stick) (obsolete)
• Notes on Building MPD for the Linksys NSLU2 ("slug") Network Attached Storage device
• HifiHacks: Linksys NSLU2 USB Audio Jukebox with MPD
• Installing on an ASUS WL500gx router: OpenWRT FullInstall
• http://www.neurostechnology.com/osd(Open-Source Device)
• iRex iLiad (e-ink e-book reader) (obsolete); [1] ipkg: mpd, mpc, gimmix
• Voyage MPD by Voyage Linux
• Motorola VIP 1710
• Bryston BDP-1