This requires an Arduino Leonardo, a SparkFun MIDI Shield, and a SparkFun Music Instrument Shield.

The MIDI shield and the Music shield have two conflicting pins, pins 3 and 4. On the MIDI Shield, these correspond to two buttons, and on the Music shield, they correspond the the MIDI in and Reset pins of the MIDI decoder chip. Because the MIDI sheild is going to be on top (the music shield needs no access for buttons etc), it's fairly straightforward to rewire the MIDI shield button pins to other pins. I chose to move all three buttons (2, 3, and 4) to new pins - 8, 9, and 10, respectively. Photos below: