D610

The first set of Nikon D610 specifications  received on Nikon Rumors are 100% identical with the current D600 model:

• Sensor: 24.3 MP (6016 x 4016 in L mode)
• ISO range: 100-6400
• AF: 39  focus point, 9 cross type, 33 point available at f/5.6
• Viewfinder coverage: 100%
• TTL exposure metering using 2,016-pixel RGB sensor
• Video recording capabilities: 1920 x 1080 30p/25p/24p
• LCD screen: 3.2", 921k dots
• Battery: EN-EL 15, using the same MB-D14 battery grip
• Dimension: 141 x 113 x 82 mm

Please note that this does not mean that there may not be some other improvements that are not mentioned in the list above - Nikon Rumors still trying to get some additional information. The fact that the D610 body size will be the same indicates that this may really be exactly the same camera, just with improved shutter mechanism just like the SB-900->SB-910 update it mentioned few weeks ago.

In the meantime the price of the D600 continues to fall - Sammy's is currently selling it for $1,799.

Source: Nikon Rumors