Several days ago, Sony shook the market with the new A7/A7R full frame mirrorless camera. Now Nikon is also going to release a new full frame hybrid retro camera within 1-3 weeks. This full frame hybrid camera will have a Nikon FM2 design, also like Olympus OM-D series. This is not a mirrorless camera, it will have a pentaprism viewfinder. This camera will be announced soon, maybe show up at Photoplus EXPO 2013.
The upcoming Nikon D610 is rumored to be announced on October 8, 2013. D610 will solve the oil issue of D600. And the only upgrade from D600 is Nikon D610 has 6 fps continuous shooting speed, while D600 is 5.5 fps.