I am getting the D800E, and I look forward to seeing how it does with HDR. I have a theory that the D800E is going to be great for HDR. My theory is this:
HDR is known to be soft and its possible that a big part of the softness is because HDR really brings out the flaws of an image. Since almost all digital cameras come with a AA filter that creates a softening effect to eliminate moire, HDR software really picks up this softness and magnifies it. I think with the new D800E which does not have this AA filter we might be able to get sharper HDR images straight out of the HDR software
my 2 cents
The resolution of the D800 is so much greater, its output without the E version, will look sharper than a D4 and it is unlikely that you will notice the difference between the D800 and the E version. The D800E does not eliminate the anti aliasing filter it just overlays another structure over to mitigate its effects. The D800E is brand new technology and you know what that usually means in the 1st model year. The Moire effect for certain patterns and scenes will drive you mad and it will be much worse with HDR because you will need to eliminate the moire pattern prior to merge and tonemap. I'll be getting the regular D800. One disappointment I have is that Nikon reduced the # of auto bracket shots from 9 to 7. And a note for HDR users, the 36 Megapixel image stacks will put a heavy load on your HDR s/w so you should test the program in advance to find out where it will choke.
Regards, Murray