So far Nikon has chosen not to sell a camera with the low light performance of a D3S or a D4 in a D700-style body. So the pattern is two full on pro bodies in a row and no "D700 version" offered. That might be a clue.
Hard to say if that pattern will continue though. The recent stat that Sendai is positioned to manufacture only 5,000 D4 a month seemed very low to me. If they were positioning to sell 10 or 15K D4 a month I might be inclined to think they are not planning a smaller body D4 sensor. It's possible though that they will time the release of a small-body-D4 with the issuance of a D4S, so that might mean a further two year wait. Very difficult to say. Maybe one other clue - if Nikon wanted to sell more D4 than ever they sold D3 or D3S, wouldn't they just come out and say "this sensor is only going to be offered in the D4"?
Another wildcard is the D3S sensor. Shame to retire it yes? Make a good mirror less with it? But really I can't see it, probably anything offered now onwards has to have a D4 style sensor due to its many video advantages. So I think the D3S sensor, marvel of photography that it is, is toast - hard to believe really.
See, Canon actually came out and said something to the effect that "the 1D X is all we are offering in the large-body line up". Although come to think of it, in the smaller-body line (5Dx) they neither have offered any clarity.
Personally I am not taking the chance of a further long wait for a D4 sensor in a smaller body, I want something better in low light than my D700, so I ordered the D4. I should have ordered the D3S back-when, but I wasted two and a half years waiting for a D700S. Anyhow, I am not bitter, lesson leaned and all that and the D4 looks pretty phenomenal