(commentary)
I just noticed that the D3x is down to US$6700 at B&H. I'm not sure how long it's been at that price, but I keep hearing rumors of Nikon doing a close-out on the D3x in various parts of the world; I wouldn't be surprised to see new D3x prices drop some more.
Thus, this is as good as time as any for me to repeat my speculation about what else might be announced this year. I expect to see no more than two DSLRs launched in the remainder of 2013: the D400 and the D4x. The D4x seems to be almost a lock, with really only the timing and the sensor choice being unknown at this point. Rumors have it that there's a new version of a high pixel count sensor floating around in test, so we will probably get something slightly better than "the D800 sensor in a D4 body."
The D400, having been postponed once, seems less certain but clearly inevitable. The longer Nikon delays a D400 the more they risk losing customers to others as well as decrease in the potential market size for the product in the first place as some consumers decide to go elsewhere in Nikon's lineup. Once again, though, the primary question is what's happening at the sensor. All the other aspects of a D400 seem pretty easily guessed at, but since the D400 would have a longer life cycle than all the other DX cameras, I think just stuffing one of the existing 24mp sensors inside would be a slight disappointment. It's clear that the D400 got delayed once. Had it made that original announce date, it would have been one of the first 24mp DX cameras, if not the first. But it seems it slipped out of cycle and now the sensor question is the big factor in when it will appear: the top end of the DX line really needs to have a top-end sensor that can last through a couple of consumer DX sensor updates and not look out-of-date (the current D300s problem in a nut shell).
The next announcement window happens to overlap when I'll be in Africa, so I suspect that this will be the time ;~). Nikon has this habit of launching when I'm off in the field, though because I'm in the field so much, the odds are not exactly zero.
To be clear: I expect one or both of the D400/D4x announcements in August. I don't expect a late announcement (Christmas surprise) this year as we've had sometimes in the past. The pressure is on the camera makers to find new products that resonate with users and push their DSLR sales up, as the compact camera market is collapsing fast enough to make the interchangeable lens cameras the only place where profits can still be found. That's one reason why I say the D400 is inevitable. A D4x, no matter how good, is still a low volume product and a very temporary boost, at best. The "right" D400 will, however, make a bigger and longer contribution to Nikon's bottom line.
That's one reason why I've not gotten too concerned about the D400 delay: I think it better for Nikon to have the right product done right than to have just iterated as fast as possible. Last Camera Syndrome is becoming a factor with more and more non-professional photography enthusiasts. The D400 done right would be such a camera for many. A D400 done wrong will make some rethink whether they need another Nikon DSLR.