westfw:
I don't think it will be as easy as you think; given the design rules that they're using, it's pretty hard to find space for anything as big as am extra pad. The MEGA board doesn't have a bunch of empty area; it's got areas that are covered with TRACES.OTOH, it's clearly possible, since Seeed has done it...
Actually, as your own OTOH points out, there's plenty of room on the Mega 1280 board for lots of new pads and traces. This is especially true considering that the Seeed board brings all the traces to pads on a PCB that's significantly smaller.
But, I don't want to get into an argument here. I would simply like to put forward the proposal (humble request) that, henceforth, pins not be sacrificed in this fashion on new Ardiuno designs. I don't know who decides these things, but it would be really great if they could consider trying to go the extra mile and leave no pins behind!
Wayne