Upload & Sell: Off
The d800 is not more sensitive to camera shake. I thought that myth was debunked a while ago.
The only way you will really notice the camera shake more is when you really crop down an image. Otherwise, normal shooting, its the same as any other camera.
Now for the OP, I went from a d3s to a d800... I had a d4 for about a month but sold it. Based on your needs a d3s sounds like the best solution. I've often thought about switching back to a d3s since as others have stated, my HD is pretty much full, like im actually in the market of buying more storage as we speak.
The d3s and d800 are really both amazing cameras but are amazing for different types of photography.