Before we start tracking the D600, here is a quick in-stock update on the Nikon D4/D800/D800E cameras. The D4 and D800 are freely available in most retailers, but the D800E is still hard to get:
Nikon D800E is currently not in stock at any of the major retailers.
Nikon D800 is currently in stock at:
Nikon D4 is currently in stock at: