Many models featured at motor shows won't ever be built, but the FCV is on the fast track to production. According to Daily Finance a car similar to the FCV called the FCV-R will be in showrooms around 2015.
Unlike most electric cars, which are powered by heavy, expensive battery packs, the FCV is powered via hydrogen fuel cells. Hydrogen cars only emit water and water vapor as a waste product. There aren't many places to refuel a hydrogen car yet, but designers for Toyota, Ford, GM and Hyundai are all hoping that cheap, efficient hydrogen will become more widely available as the technology proves itself.