I used my old Nokia BT receiver for I while, but it has certain limitations driving me to build my own MPD server.
Selecting a suitable hardware wasn't that hard, not because the OrangePi Zero is such a perfect piece of electronic, but because of the lack of alternatives.
I looked for a cheap, low power board with analog audio out and if possible IR and wifi. So the OrangePi Zero appears the best choice for a low price just a bit above €10 including shipping.
All in all it works quite good, even if connecting through ssh/wifi can be slow. The only big problem is the buggy wifi chip, as the built-in powersave feature often makes the board unaccessible. I worked around that behaviour by pinging the board every 5 seconds from another arm device I already use as NAS and IoT base station. Using an IR remote provides a responsive possibility to control the system too.