http://forum.xitek.com/thread-1022917-1-1-2.html
(in Chinese)
It is said that the pictures were leaked from Nikon's Thailand factory but most importantly they look real! Btw, the D600 seems to be more compact than all other existing Full Frame bodies and all people have been saying that it will be sold cheap. So, I think Pentax is really doom this time, or at least I would say the 135 K-mount will become useless sooner or later and many Pentaxians have migrated just because the lack of a Full Frame body in the Pentax land, especially for those long-time old loyal supporters! >:-(
Hey, Pentax, are you still too busy in working with some new f/6.7 to f/7.1 zoom lenses in K-mount such that there is still no Full Frame body of any as no research nor resource of any is put into that? :-o