This isn't a concept car. Smart actually made these and offered them to the public, albeit in limited quantities. Now one of them is crossing the auction block. With Smart city cars populating downtown streets in cities around the world, there might not be very much that's rare about Daimler's smallest product. But in 2002, the company unveiled the Crossblade.What might have otherwise remained a concept car was actually put into production, despite having no windshield, roof or even real doors to speak of. What it offered instead was a unique take on open-air motoring. It weighed only 1,600 lbs and its 600cc engine was tuned by Brabus to 71 horsepower. Source: Carbuzz