I just spent a little time at my local shop handling the D600. I discussed the price issue with the sales guy. He noted that Nikon does this sort of thing all the time with all of their products. And that there doesn't seem to be any logic or rhyme/reason to it. Sometimes they will offer a $100 "intsant rebate" on a camera for a while and then that will go away and then they will offer $150 and then $50... None of it makes a lot of sense.
They didn't have any in stock (I was handling one of their rentals). In fact their stock seemed to be pretty much wiped out in general. Ultimately I ordered the 2 lens kit (24-85 and 70-300) from JR.com for $2390.