See the latest news report at the Pentax User (UK):-
http://www.pentaxuser.co.uk/news/pentax-645d-wins-japanese-camera-award-350
Or the original Hoya press release at the Pentax Japanese homepage:-
http://www.pentax.jp/japan/news/announce/20110518_2.html
(in Japanese)
After some prolonged "dead-air" in the Pentaxland without any special news recently, I think this news is somehow refreshing, although 645D is just *another* system that I would probably never invest.