Boy, that was fast. You can already preorder the just-announced Nikon D4, which will ship in February, from Amazon. The Verge has a hands-on preview already posted. Vlad Savov writes:

You know you're in for a treat when Nikon decides to upgrade the very top of its camera range, the single-digit DSLR flagship. Taking over from the D3s is the D4, a $6,000 camera that gleefully upgrades just about every spec from its predecessor while also weighing less and lasting longer on a smaller battery. Notable features: * 10/11 frames per second continuous shooting in FX-format for up to 150 frames * Nikon FX- format (35.9 x 24.0mm) CMOS Sensor with 16.2 effective megapixels * Full 1080p HD broadcast quality video * View simultaneous Live View output on external monitors and record uncompressed video via HDMI terminal * Multi-Area Mode Full HD D-Movie: FX, DX (1.5X crop) and New 1920X1080 (2.7X) Crop modes settings They also have posted an excellent comparison of the D4 against the D3s, D3x, Canon EOS-1D X, EOS 5D Mark II, and Sony Alpha A900. And finally, for those of you who just want to look at it, a photo gallery of the D4 shows you every angle you could want to see. Also, Strobist noticed something very cool:

WTF? #NikonD4 has *built-in* remote control, focus AND xmitting via iOS devices? Video: bit.ly/xCiJQe #Nerdgasm
— David Hobby (@strobist) January 6, 2012