I have recently had discussions with some Nikon engineers and execs visiting Australia. Of course, absolute details don't exist, but I can gauge reactions, and read between the lines.
I expressed surprise about the D700's announcement. I thought surely Nikon would have released it maybe next year. There was of course, great enthusiasm with the Nikon guys when talking about the Nikon cameras, but there were some things I noticed.
It seemed Nikon were very eager to release the D700 now, rather than later. My tea leaf readings on this are; most of the professionals that wanted the D3 , now have it. The long wait for a D2H replacement was grabbed the moment it became available.
The major rush to buy the D3 has slowed so releasing a D700 now will not cannibalise sales of the D3 like some people think might happen. In fact, many D3 owners are talking about picking up a D700 has their second camera.
It would also be fair to say that some D3 owners would never have bought the D3 had the D700 been available at the same time. THAT would be cannibalising sales, though there will always be those that need the requirements of the D3 (extra fps, dual cards, 300,000 shutter life etc).
The words 'only 12MP' came up a few times. I am of the belief that there's a couple of things happening here. Nikon wanted to ensure they could maintain the momentum they have been creating especially with the release in about a month of Canons 5D replacement.
And since the 5D will be at least 16MP (and my guess possibly even 18+), the D700 would have been criticised for not matching it. Releasing it now, means it's not 'behind' Canons latest release when it does appear.
This below is pure speculation rather than anything concrete but speaking with the visiting engineers, it seems Nikon have something left up their sleeves. The D700's release seems to almost be the beginning of something new. It doesn't feel like the usual D3x rumours though, ie a 24MP camera in a D3 body.
I also know it's been discussed (or wished for) in the past but the feeling I'm getting is the new camera is more substantial. Could it be the modular system that has been rumoured? Wouldn't it be great if you could just 'drop in' the sensor you wanted. Be it a native 25,000 ISO black and white sensor for surveillance work or a 26MP 'studio' sensor or a full colour sensor when that becomes available.
Could we even get manufactures like Fujifilm developing a 'drop in' sensor module? It may be closer than we might think.