Really Right Stuff thinks the Nikon will release their next-generation DSLR camera in the summer of 2011. It'll be called the D4.
This is a sensible prediction. Nikon has waited about four years between each major upgrade to their pro-level DSLR line. The D3 came out in 2007. So, it won't be a surprise when the D4 debuts next year.
What is surprising is that RRS put out a catalog with that information. I'm betting Nikon is not happy about this.