The D800 might be off the table. I think my friend low balled the price and is now having second thoughts. I don't blame him as I certainly wouldn't sell mine for $1200 if I had one. Still up in the air but I'm now looking more closely at the D610 and a7ii.Get the D800 you won't be sorry. When you shoot at that many pixels you can crop in to images and find all kinds of magical treats you didn't know was there.
There are professional photographers that would disagree with you. Check Trey Ratcliff at http://stuckincustoms.comJust avoid the Sony, it's a great device but still far from catching up to DSLR flagships like d750/d800
As much as I would love a D750 its out of my price range. No point in buying it if I'm not going to have a lens good enough to take advantage of the camera.@OP Ah Ha The reason I said don't rush was more figuratively. I know you're not rushing because you said the word "soon". My first DSLR I chose because of the price eventhough the salesman tried to get me into a body with higher price (so I thought). All I saw was the price, and not function. Now I see that these cameras are very similar, I try to look my style of shooting. How I'm going to use it. What features I really want to use in a camera. You already know about Nikon environment. So put all that in the pot and go with the one that fits you best. I would kick out the D610 and put on your list either the D750 or D800.
I've played with the D610 and D750 in the store and I really love the feel of the D750. The LCD screen moves nicely too. I thought it would be all clunky like some of the camcorder styles LCD screen but it not. Everything else feels like a D610 but lighter. I know when I use the 24-70mm lens on my camera it can get heavy after an hour of using. The lighter body might be helpful.
D800 is great. That would be awesome if you can find one within your budget. Good luck.
At this point I'm leaning towards the Sony. Dollar for dollar I think it's a better value than the D610. I'm still not going to make a final decision until I visit B&H and hold it in my hand. Besides no one has it in stock anyway.