I use an MP3 trigger with a Rabbit BL4S110 SBC. It would be great if I could have the MP3 trigger on an X-Bee format PCB so I could plug it directly into the X-Bee socket on the SBC. The only components needed on the board would be the VS1043B codec and its associated discretes, the CY8C29466, and the SD socket. A great improvement would be to add a couple of decoupling caps on Left and Right audio so they could be referenced to GND rather than GBUFF. Also be very useful to put an opto-coupler in series with status LED so this could be used as a gating signal for an audio amplifier and general status feedback to the SBC.