at the iaa 2002 in hannover a new unimog series was announced:
the U 3000/4000/5000 .
these are modernized U427, for use in difficult terrain.
now only the U300/400/500 and the U3000/4000/5000 series are still built, and production was transferred from gaggenau to woehr (not far away from gaggenau).

at the moment, the only information available is in german, at http://www.mercedes-benz.com/d/ecars/unimog/unimog_iaa2002_1.htm

information about the u300/400/500 (series 405) is available at http://www.mercedes-benz.com/e/ecars/unimog/default.htm