Today I received some information confirming Thom Hogan's latest post (probably from the same source?): Nikon will announce D700 and D3s successors on August 24th, 2011. The D700 replacement will be available in Fall 2011 and the D3s replacement will be available at the beginning of 2012. Both will be produced in Malaysia. The D700 successor will have 24 MP, the D3s successor will have 18MP. Both cameras will have new AF-system and many new "astonishing" feature.
I do not feel comfortable with this D3s/D700 replacement rumor, since I still believe the announced combo will be D4/D400 but this is the most reliable info I got so far. We don't even know the exact model name of the D700 replacement. The lower MP count on the D4 compared to the D800 (or whatever the name will be) is also questionable. This will be the first time a company will announce two different full frame models at the same time. It is possible that someone is spreading false information in order to misinform the public and increase the hype on announcement day. Nikon has definitely changed the way they handle new product announcements and at that point everything is possible.
The worst case scenario for August 24th is the announcement of Nikon's mirrorless camera only. This is quite possible, since we have already seen a reliable leak of the new mount.
[NR] probability rating: 80%