Due to the overwhelming support I get on this forum I wish to share with others the pin-outs and port assignments for the 2560 as I had trouble locating them and now I have summarized it, to make easier for others.
Very nice job, thanks for sharing this. You might consider title change to AVR mega1280/2560 as they both share the same pin functionality.
Lefty
Looking over the signal names for pins 50 and 51 you show them both named MISO, which seems to be a simple mistyped for the proper signal name MOSI assigned to pin 51. You show it correctly in the Port B breakdown.
Lefty
Mis-label on MISO fixed.