I do have my 3-years-old granddaughter for a sleepover tonight. Poor thing's had to deal with Grandpa taking pictures with his newly-acquired 85mm f/1.8D.
The only camera on the market that would lure me to FX from my D7100 is the D700, which you have one for sale. All I've read about the D700 is it was a one-off, too-good-to-be-true-set-of-features-for-the-price camera, that Nikon will most likely never repeat.
Yeah (Insert heavy sigh) it's a remarkable camera. I love it. I've driven most of Nikons camera bodies since the D200 and there is nothing like it for the money. Actually I prefer it to the D600 or D800. Even today, long in the tooth though it may be, it takes great pictures. It so easy to use. The buttons are exactly where they should be. I know my way around the camera with my eyes closed. You can reach every control you need to while you're in the process of shooting and never take your eye from the viewfinder. The auto white balance is outstanding, the ISO performance is all I've ever needed and it just feels so good in your hand.
I hated to sell the 70-200 but selling my D700 feels like I'm selling my dog.
It has to be done though. With my back I can't carry a bag full of camera equipment and lenses around any more. And I can't afford the Fuji X system I want without selling my SLR stuff.