Some excellent observations from all who chimed in - and I certainly appreciate the insight!
Based on what I'm hearing and reading, I think a move to the D800 might make sense for me.
About the only major concern I have is over something that was posted in the Mansurovs review about the D800, which dealt with Live View.
I use Live View a great deal on my D3s, and have it set so that when I press the center button, it zooms in 100% for critical focus.
Here is what the reviewer said. Is this a deal killer? Of course most of the time, I don't have to see exact detail to know that it's accurately focusing where I place the focus point, especially when I get the green confirm box. I suppose for testing lenses or Macro work, this would be more of a limitation.
But if the Live View focus is less accurate than the D3s in general, that's a different story altogether.
"While the camera has an impressive live view implementation with more features than on any previous DSLR, there is one very disappointing news – the magnified view on the D800 is not 1:1 pixel level. Because it interpolates the image instead of showing 1:1 pixels, the image appears with much less detail. I noticed this while testing lenses and it was a very annoying problem, making it difficult to see if the focus is accurate or not."