I received several emails from readers that a new batch of Nikon D850 cameras started shipping today in the US (see also the reports on the Nikon D850 Facebook group). I believe the second batch will still not be enough to cover all existing pre-orders.
Check D850 availability: B&H | Adorama | Amazon | BuyDig | BestBuy | Cameta | eBay | WEX | Jessops
Follow D850 on Facebook: Nikon D850 Page | Nikon D850 Group