This project has been sitting on the back burner for a loong time now.  Now that I have small window of free time, I figure I'd come back around to it and do the rev B board.  I had a couple errors in the layout for the first version.  I changed the SD card interface so it's a pass-through - I don't see a way around it so there will be a few pins visible on the top side.  

I also decided to make a few other changes.  I wanted the top of the board to look a little cleaner, so I moved all the passives to the bottom of the board.  I also figured I'd implement the music output too. It's just two caps, a resistor, and a 3.5mm barrel receptacle.  There's room for it on the bottom of the board where it will be hidden.