EDIT: Just created an SVG, it had two issues but I uploaded anyway. It looks like crap in a browser, can you guys try in a graphics program.
Top left of the excellent diagram, explaining the color coding: "per A" / "Per B or X" - I am confused what the little black corner signifies.
Actually I've been wondering if it's worth differentiating the peripheral mux option used. After all it has no real bearing on the average user and more experienced SAM users will either know this or will soon find out.
That's on the Mega, with the Due SPI is only available on the 2x3 SPI header.
thanks a lot for your work!