I have no reliable information that Nikon will release a D700s/D700x camera on October 15 (the actual release date may vary +/- one day based on your location). It also doesn’t make sense to release two PRO level cameras at the same time – I know, D3 was announced with the D300 two years ago but they had different sensors, etc.
There will be a second camera, or line of cameras announced in two weeks. The reports on that are wild and go from a new small digital Nikkormat (unlikely) to a Nikon P6000 replacement and maybe even a Leica X1 clone. It will be something new rather than a replacement from of an old model (but definitely no DSLR or D700s/D700x). Using Google translation to “decrypt” messages from Asia certainly doesn’t help… (sorry, I cannot use [NR] readers as translators for privacy reasons).
As for the lenses, Nikon AF-S 16-35mm f/4G ED VR and Nikon AF-S 100-500mm f/4-5.6 IF-ED VR sound promising (even though the 100-500 is expected next year) and possibly a third, wide angle lens. I expect all announced lenses to be full frame.
Here is the break down of probabilities based on the information I have:
Of course all of those are just rumors and they may change at any time. Stay tuned!