In a brief statement today Nikon has confirmed they’re working on the 5D.
“Development of Digital SLR Camera Nikon D5
November 18, 2015
TOKYO – Nikon Corporation is pleased to announce that it is developing the Nikon D5 digital SLR camera, which represents the next generation of professional Nikon FX-format models.
The new Wireless Transmitter WT-6 and Speedlight SB-5000, which will be positioned at the top of Nikon’s Speedlight lineup, are also being developed.
Through the combination of this next-generation professional camera offering an even higher level of performance, these advanced accessories and the rich lineup of existing NIKKOR lenses, Nikon is pursuing further possibilities for imaging expression.
*Details including release date and suggested retail price for this product have not yet been determined.”
No specifics or dates have been announced but some say (like the D4) maybe we’ll see a first glimpse at CES in January.