I dont know how many have seen this since Philip is know better in the video realm, but he's been playing with a 645z for a few months now
Shadows and Detail: A love letter to the Pentax 645z | Philip Bloom
"This is less a review and much more a collection of my thoughts and feelings about this utterly magnificent camera. I am far from an expert on reviewing a camera’s ability to take stills – I will leave that to the pros. My speciality is of course video cameras, moving images, but this camera is too special to me to not do a post on."
seems he likes it .....