Those look great, Len, and it made me all of a sudden want to raid the pantry for that chocolate bar :-P
I never said that because a lens was an old lens that it was not up to the task on a D800 (i.e. I wasn't singling out the 80-200/4.5 in my post). Old or new doesn't really matter. There are plenty of older lenses that are sharper than newer lenses and vice-versa, as you well know.
You have also introduced a third camera now into the discussion, the D3X, whereas I was discussing the 12MP D700 versus the 36MP D800 per the original posters request.
The D3X has a vertical resolution of 4032 pixels, so you're 80-200 needs to yield about 2000 line pairs/picture height, compared to a D800 which ups the ante to just shy of 2500 line pairs. The D700 at 2832 vertical pixels is way down at 1400 line pairs, which is significantly less than the D3X, by about the same amount that the D3X is less than the D800. There aren't many lenses that don't resolve 1400 line pairs - at least in the center. At 2000 you'll start dropping some lenses. At 2500, you'll drop even more. If there was an FX 144MP sensor (that wasn't diffraction afflicted) then there probably wouldn't be a single lens that Nikon makes that could approach it. On the converse, if there was a 1MP FX sensor that was roughly 700 x 1400 pixels then all your lens would need to resolve would be 350 line pairs. Get out that old hand magnifier
Just saying that any given lens may not let you get the most out of your D800. It may give you good results on a D700 and probably on a D3X, but it could be that when you put it on a D800 you really don't get any additional detail than you were getting on the D3X. You said yourself that you see "mostly better resolution photos with nearly every lens" so you apparently have some lenses that are not up to the task even on your D3X. Going to a D800 you might find a few more lenses added to that list.
I do want to say that, even if a given lens doesn't provide enough resolution on a D800 versus a D700, it shouldn't produce a worse image on the D800, and you might see some benefit regarding ISO noise, etc. We're just talking strictly lens versus sensor resolutions.