Today Nikon has release a firmware upgrade for the Nikon D2x and Nikon D2Hs cameras. It improves AF performance and fixes a problem with AF assist with certain Speedlights. White ballance is corrected for Incandescent, Direct sunlight, Cloudy, Shade, and Choose color temperatures. Also correctins have been made in the Dutch menu translations.
A few people who have installed the upgrade on their D2x claim that the noise reduction is smoother for ISO 800 and 1600 images. Check out some examples here.