Custom designed sets (with instructions) by Shoji Kawamori (Macross mech designer):

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=161353

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=224448

From wikipedia:

In 2006, Lego commissioned Shoji Kawamori to design combination models using various Exo-Force sets. The combo-units were called VAN-Force; they featured custom decals, which were given away with purchase of bundled Exo-Force sets in Japan. The first VAN-Force design used the Stealth Hunter and Grand Titan. A second combination design called "Raiden" (which uses the Stealth Hunter, Grand Titan, and Thunder Fury) was revealed in December 2006. In Kawamori's Macross fashion, the units can transform between from robot to vehicle. According to Exo-Force writer, Greg Farshtey, Lego does not have the rights to reproduce the VAN-Force design for sale in stores.