As a longtime Pentax 67 user, I'm very interested in the 645D. Of particular interest to me, is how well the 67 M* telephoto lenses perform at this resolution, especially the big M* 800/6.7 ED IF.
I'm located in Honolulu, so if any 645D owners are planning a trip to our little rock, I invite you to spend a day on the beautiful north shore trying the three M* telephoto's. I'll supply the Wimberley head and a Berlebach Uni 17 tripod.