Actually I believe this anouncement to be a very significant one. To my knowledge there is no 36MP+ camera system at this price point. The Mamyia equivalent, the only one I can think of, is more expensive when you consider the lenses.
The trouble with this Pentax camera is that's probably too late. By the end of the year we will talk 30MP DSLR's from Nikon and Canon and I believe that considering Zeiss and top of the line Canon and Nikon lenses, the 35mm format really started to catch up in the optics sector too compared to medium format.
This camera is still great news for medium format lenses owners though, and if no major technological breakdown will occur in the near future, it might be possible to see Canon and Nikon jumping in the larger than 35mm sensor market due to the increase in photosite density. If you wonder about the form factor, the Leica S2 is a good example of what can be done: a medium format sensor (not fullframe) in a DSLR body no larger than D3X. From this point of view, maybe Pentax move is a wise one.