5 fps (same as the D700, the D800 has 4fps)
2 SD card slots with Eye-fi support
Build-in retouching images functionality
Built-in flash with sync speed of 1/250s
Two user settings: U1 and U2
Fn button
GPS
HD video
The sensor inside the D600 will probably be 24MP (made by Sony, modified by Nikon)
The new camera will be marketed as an entry level full frame camera
Auto DX crop mode
In-camera RAW editor
Built in time-lapse functionality
Possibly with build-in HDR
Possibly with integrated GPS
New external battery grip
To be released this summer
The D600 will probably not have an internal AF motor, which means it will work only with AF-S lenses (just like the D3200 and D5100)
The price of the D600 is rumored to be very low - maybe as low as $1500
Announcement before Photokina (September 2012)
One or more low-priced f/4 lenses will be announced with the D600. For example, Nikon recently filed a patent for a 24-70mm f/3.5-4.5 full frame lens which seems to be designed for a cheaper FX DSLR body
At that point I feel comfortable to raise the [NR] probability for the Nikon D600 to 60%. Some of the listed specs may still be inaccurate, but I think I got the most part correct.
http://nikonrumors.com/2012/05/09/more-nikon-d600-specs.aspx/
2 SD card slots with Eye-fi support
Build-in retouching images functionality
Built-in flash with sync speed of 1/250s
Two user settings: U1 and U2
Fn button
GPS
HD video
The sensor inside the D600 will probably be 24MP (made by Sony, modified by Nikon)
The new camera will be marketed as an entry level full frame camera
Auto DX crop mode
In-camera RAW editor
Built in time-lapse functionality
Possibly with build-in HDR
Possibly with integrated GPS
New external battery grip
To be released this summer
The D600 will probably not have an internal AF motor, which means it will work only with AF-S lenses (just like the D3200 and D5100)
The price of the D600 is rumored to be very low - maybe as low as $1500
Announcement before Photokina (September 2012)
One or more low-priced f/4 lenses will be announced with the D600. For example, Nikon recently filed a patent for a 24-70mm f/3.5-4.5 full frame lens which seems to be designed for a cheaper FX DSLR body
At that point I feel comfortable to raise the [NR] probability for the Nikon D600 to 60%. Some of the listed specs may still be inaccurate, but I think I got the most part correct.
http://nikonrumors.com/2012/05/09/more-nikon-d600-specs.aspx/