E-Cube - DIY Zero Energy House Kit
if i recall, there is a blog on greenbuildingadvisor.com about that whole decathlon event. cubes are the ideal shape, from an energy standpoint. as for prefab, it will get more popular here in the near future. "pre-fab" still carries the stigma of a 1960's trailer. i've seen the framing up of a few nelson homes (no affiliation to them, so i don't get paid or laid for saying this), made in canada, and i was impressed w/ the accuracy of the walls, windows, etc. i don't care for their use of osb, but that is debatable. on youtube there are vids of some european factories, and if a company GAFRA about their workmanship, there is no reason they can not build a super quality house and ship it out.