I am blessed/cursed with any early, low-numbered D3X which is now pushing 440,000+ actuations. I still rely on it as my primary camera for fashion catalog and magazine editorial production. I bought the D3X with my NPS priority purchase invitation and got it on one of the first deliveries. At the time it was introduced it was standing way ahead of any other DSLR and was really instrumental in helping me get back to DSLR from MFDB (Leaf/Hasselblad) for catalog and magazine production. I'm not saying that it was the perfect studio camera, but it has served me well for many years now. Unfortunately it is on its 3rd mirror assembly--both failures were on lengthy location trip assignments.
I'm starting to get a little worried about the life span of the body. I keep mining the rumor mills for word of a new pro-level camera with at least the same sensor size as the existing D3X. I have a D800, but it doesn't take much handling to realize that it was not created with the same robust build-quality as the D3 and now D4 series cameras. It is simply not a replacement for the D3X for a number of reasons. While I can see the D4/D4s as an advance and update for the D3/D3s, I don't understand the interval in updating the D3X. Neither the D4 or the D4S are, in my opinion, geared for the fashion/catalog/advertising shooter. I've been away from photojournalism too long to give an opinion about how they are suited for newspaper work, but I know people who love them for that.
It does seem natural that they would create a D4X with at least the sensor size of the D800/810 (if not the Sony 46MP sensor) in a pro build body before they would do a D5 or a D900, right? I'm feeling left out...
D3X, D800, 17-35, 28-70, Zeiss 55mm OTUS, 85mm Zeiss CF.2, 85mm PCE, 70-200 VRII, 105DC