Have just touched, put it in hands and inspected a 645D and its kit lens without powering it up (which is exactly like what Lance B had done for a Nikon D700 before he subsequently decided to buy it!) and below are some of my findings and very brief impressions:
1. The body is large and heavy;
2. The kit lens is in normal size for a Mid-Frame prime but it was felt lightweight (especially after I held the body and then the lens);
3. The combo is huge and very heavy! Well, it is really an aircraft carrier of a DSLR! :-o
4. The body is very well built, felt very solid but the outer shell felt a bit plasticky. Well, it's made with metal alloy, right? Maybe it's the coating/painting on it that gave me that feeling;
5. Despite the 645D is made in Philippines, I do have good impression on the workmanship as it looks.
6. The anti-reflection coatings and (transparency of) the optics of the eyepiece is pretty impressive. It should be made of glass for the optics, I guess, unlike all those other Pentax APS-C DSLRs which the optics in the eyepieces are all plastics.
7. The rear 3" LCD monitor looks rather tiny on the back of the 645D. And it lacks any anti-reflection/anti-glare coating so that it just reflects white light. Umm, I think my Sony NEX-3 is better here as it has deep colour anti-reflection coating on the surface of the LCD (which is roughly of the same 0.9M+ pixels resolution as the one in the 645D - but in 16:9 Aspect Ratio instead of 4:3);
8. The kit lens is a SDM only lens and it is "Assembled in Vietnam", as printed on the inside of the lens rear. It is weather-sealed for the orange red rubber ring around the lens mount. The materials and texture are just plastic, which is similar to that of the later Pentax DA lenses like the DA17-70's;
9. The aperture and blades of the kit prime form an almost perfectly round/circular shape opening for all f-stop values as I gradually pushed the aperture coupler and inspected it. Well, the bokeh of the lens is supposed to be better then, right?
10. Last but not least, the kit set is really very expensive and I will not buy it! ;-D (How can I live for the month to come if I spent all my hard-earned money for a whole month for just a camera (i.e., just a body + one lens)?! :-o Moreover, my wife will surely kill me if I did that!! :-{)
I guess the price of the 645D kit could be reduced. If you're not in a hurry to use it but still want to get one, just wait a bit longer until the price is to be stable. Btw, if you're far richer than me and have no wife that would kill you on the purchase, just Act Now! ;-)))