When will a replacement for the Nikon D700 be available?

When will a replacement for the Nikon D700 be available?

That would be up to Nikon

http://nikonrumors.com/

Either you buy the next higher model or settle for the D700 now. If you wait, you'll lose more photo shoot opportunities. It's just a matter of knowing what to do. The camera is only a tool. You should be able to take any shot the same way (almost) with any camera.