I had a customized version of this made for my Arduino Mega 2560 project. Includes Sparkfun MP3 and VeeAR EasyVR shields.
Excellent design overall, I'm quite happy with it.
The USB and power holes aren't quite tall enough in the design. I'll have to file those down a touch. No big deal, I need to drill a couple of holes anyway for my audio output port and microphone.
Thanks for the thing!