As a 6x6 shooter, I had always considered 645 to be a bit of an unsexy format.
Well, fate has moved me into the Mamiya 645AFD system, and I was playing around with cropping in PS and discovered it is actually quite sexy. Just the tiniest sliver of cropping for a natural 5x7 shape, and only about 7% crop to get an 8x10 shape. See attached samples; black is the full frame.
Not bad! I hereby apologize for my previously ill 645 karma.