Koolance, specialized in watercoolers, showed their cases with integrated watercooler. While these are nice, they were already available before CeBIT, and lots of info about them can already be found on the net. To attract attention to their stand, they displayed a really cool experiment: an "immersion" cooled PC, where all components are in a "fishtank" filled with a liquid that is electrically nonconductive, but has a high thermal conductivity.
from http://www.heatsink-guide.com/cebit02/cebit02-3.html