I copy here part of the last comment in my blog, since it is directly related:
For amateur photographers like me, the relevance of this camera is rather small: I would never spend that amount of money for a hobby, and it is clear that only professional photographers, or very rich amateurs, are the target of the 645D. But I find interesting that, after the merging with Hoya and the many speculations on the future of Pentax in the current, very troubled economic waters, still Pentax decides to release a flagship, extremely expensive, professional camera like this. I remember now some recent comments, posted in
Luminous Landscape, where they reflected on the actual meaning of the Nikon D3X and its $8000 tag.
I found particularly interesting this paragraph from that article:
Quote: Excepting possibly only Leica, Nikon has a sense of its place in history like few other companies. Unlike some large corporations who are simply motivated by market share and the bottom line, Nikon actually cares about its perceived role in photography. The company thus appears to sometimes make product decisions based on more than financial considerations. So, when it comes to the D3x, what we are seeing may well be a corporate statement by Nikon, much as was made with the F6. We're back in the game, and we don't give ground in any market segment.
In my view, the decision of putting actually in the market the 645D is a similar movement from Pentax, compared to what Nikon has done with the D3X: it possibly has little financial logic, but it will be of high value to evidence amateurs & connoisseurs alike that yes, Pentax has been and keeps on being a top notch photography manufacturer, whose cameras and lenses have nothing to envy from anybody.
The lenses statement is rather clear today for anybody with a bit of attention: the limiteds from Pentax are a legend per se, and you can often read envious comments from Nikon or Canon users. Now with the 645D and the upcoming successor of the Pentax K20D, I bet that more photographers will realize that Pentax cameras are very serious business too. And this might constitute the core statement from Pentax, behind the release of the 645D.