Nikon will have another announcement in October, 2011. I do not have an exact date yet, but the week of 17-21 looks right. Unfortunately, there will probably not be any full frame DSLR cameras introduced next month. I have no idea what's coming and would like to again lower your expectations by saying that next announcement will not be exciting. If I am wrong, I am sure you will forgive me because you will be busy playing with your new D800/D4. I really prefer this conservative approach which worked pretty well with the red D3100 and the mirrorless camera announcements. If Nikon doesn't announce a full frame camera next month, the chances are very slim for another new product introduction in late November/December (Nikon has done it in the past).
And always remember: no leaks = no announcement!