I commend(and thank)Michael, Bill and Charles for taking the time to put this test together, and I have no doubt that by processing these raw files and printing out the files as large prints, we can learn about the relative resolution of these capture alternatives. However, it is unfortunate that the weather did not cooperate so that the captures could be real world landscape photographs that would illustrate the differences in these capture alternatives in terms of dynamic range, film "likeness" and other subjective parameters as opposed to a controlled lighting studio shot of inanimate objects. Perhaps another time.
I would also like to see a real world landscape photography comparison with raw captures from the Phase One P45 back against the Leaf Aptus 75 back and perhaps the Hasselblad 39MP back as well. Michael already has the P45, and I would not surprised if Leaf would be up to the challenge and loan an Aptus 75 to him for that purpose. The recent shootout may be helpful in informing your decision as to whether you "need" the 39MP of a P45, but it won't help you decide if the P45 is the right choice as against the Aptus 75 or the Hasselblad.