newton, i don't see the d800 as an upgrade of the d700 as you say; its a very different tool for diferent purposes.
i currently use a d700 togehter with a d300.
i will be getting for sure a d800 or d800E , but my main camera will be the d700 as i don't all my images beeing so huge . my d800 will probably work as my dx camera instead of the d300 and for those very special shots where i foresee the possibility of printing real big i will use the d800 fx mode. in this way i will have 3 main tools when using my d700 along with the d800.
i also think a d700s with 16MB and 100% viewfinder would be nice.