A user at dpreview forum has posted first two real life images of Nikon D850 compared to Nikon Df. The Nikon D850 is rumored to be announced August 16th, and the US price for D850 body will be around $3,600.
From dpreview user:
I do not have the camera. I did hold it, snap a couple pics of my wife, deleted them (too much detail). I did not have the opportunity to really dissect the camera. A family member works for a company in the industry. I was totally surprised that they had one. It felt solid, but compared to my Df it was huge.