It seems that some missed I did not select the D700 as the ideal camera, I will probably get it with some other material in a package too good to let go.
If I had the D7000 I would 100% be looking to match it with a D600/610 same layout
Layout would not be my main concern, I want to use different cameras for different purposes.
1) I still have a point and shoot, to point and shoot. (old system)
2) I have a very small mirrorless, for the size and the crop factor. ( I sold one old system to finance this partially)
3) I have the Nikon D7000 for a more photography approach since 1 year, still learning.
4) My issue is with low light photography, mainly for slow wildlife in the twilight. That is where I´m looking, the D700 will not be sufficient (from hearsay), I do not believe the D610 will be either.
P.S.: I think replacing the D7000 with the D4s is the ideal solution (combining 3 & 4), but I will not find it for my budget and I do not like heavy cameras at this time. So what I´m hoping for is the D9300 to be the first APS-C to be really good at high ISO, be it at 8 Mpix, but even then the price will be D610 like.
My first Nikon was a D700 and then I got my wife a D7000 which I used as a backup camera. Well, doing some comparison shots I realized that the D7000 had better pixel resolution even though I liked the depth and feel of the D700 larger format images. Even though they had what looked like more optical detail, that just wasn't being resolved digitally to the same extent as on the D7000. Further to that, the D7000 was just quicker in autofocusing, got the exposures correct every time (not the case with the D700), and so I decided to sell my D700 and get a D800 (that was two years ago). I still have the comparison shots I could post later (they are on my home computer). I agree....look to a second hand D610 (not D600). Don't get me wrong, I loved my D700 in many ways, but to me the image quality was foremost. Also, the D610 and the D7000 both have partial magnesium bodies and weather sealed so pretty much on par with the D700 in terms of build although yes the D700 is probably a bit more rugged but not by much.
Low light photography, mainly for slow wildlife in the twilight, does not require:
1) AF; generally the AF refuses in low light, so it is not my main concern.
2) to be the best in daylight. I do believe that the D7000 will be better in normal situations, so the D700 would be a second camera.
3) to be the best camera. The D800 is double the price of the package I´m looking into. The D600 is only a little bit cheaper since the D810 was announced. Nobody seems to really want the D700 anymore, so the prices are falling + offer is high since most people are replacing it with D610, D810 or D4S.
4) perfect metering. I would be working manual all the way.
What I really would need to see are pictures at ISO 12800 or ISO 25600 with a candlelight scene in a black room. That is the test I would do to see if I keep the D700 or not. From what I found I´m not convinced (D610 also lets down against the real champions in this).
For those that are pro D600/D610 against the D700:
1) Yes the D600/D610 have advantages over the D700.
2) Do those advantages justify the price increase? For the photographer that is asking the question? => so depends on the offers available and personal situation more then anything else
3) The D700 has been used professionally for years, if I could make 1 picture that approaches the best pictures made with the D700 I would be on the moon. The camera only helps a little bit in photography. I´ve seen i-phone pictures made by professionals with a quality I can not approach with any camera. => so no I do not need the D700 (that is not the conclusion I wanted to end with)
Edit: Picture to compare low light capabilities (I prefer the new dpreview tool, but it does not have the D700):
It is not real life, but it proves I really really need a D3s for what I want to do. GAS kicked in again.