The new Nikon Quick-Draw Strap is now shipping and is currently in stock at B&H. The strap was announced with the D4s in February and was developed in cooperation with BlackRapid. Product description:
"The Black Rapid Quick-Draw Strap from Nikon is an ergonomically designed and comfortably padded gliding shoulder strap that holds a DSLR with an attached lens. To use your camera, simply glide it up the strap for secure and convenient access. When you want to keep your DSLR from moving around there are locking bumpers surrounding the DSLR to limit your camera's range of motion. It also includes a quick-release stabilizing strap under your arm for even more stability. A carabiner-style locking connector holds your DSLR via the tripod socket on the adjustable length strap and allows for quick detachments."
The smaller version (Quick-Draw Strap S) is still not available.