so if you're looking at this camera seriously,
start buying Pentax 645 lenses RIGHT NOW. cause we all know, when the system ships, and if its good, prices will sky-rocket!
Pentax 67 lenses should be usable through the Pentax 645-to-67 adaptor; I se no point putting such a small sensor in an actual 67 body.
naw, I was thinkin a 6x7 sensor baby! no futzing with 645 anymore, bring out the big guns! 40mp, 6x7 sized sensor(with sensor+ type pixel binning), so making a 10mp 6x7 sensor with ISO 1600? yum.....
will it happen(even in the next few years?), NO... unfortunately... but there would be a 100% chance I would buy it though, even if iso 800 was the highest I could go clean with little or no noise.
but personally, I'd prefer a 6x7 back for my RZ.