Okay, this might just be a rumour, but I've heard that Nikon will release a D4 model before Xmas. No information is available, yet, but you can probably safely assume this will be the D3X and more.
Of course, it's easy to predict that the next Nikon flagship SLR will be called the D4, and based on their release history, you can estimate that it will be released in the next six months, but this was overheard from a reliable source.
More information when it becomes available. Stay tuned!