Apparently, the 2004-2007 SmartCars in Canada came with the turbo diesel (800 cc) but will be switching over to the gasoline model now that the gasoline version of the car will be sold in the US. Plus the fact that the diesel version doesn't meet the new requirements. When I read that it was only going to do >40 mpg US or 48mpg IMP - I was dumbfounded as the diesel version gets much higher mileage! However for the money, a diesel Jetta (1100 km range!) or Civic Hybrid will give you a more satisfactory experience.
They are apparently very popular in Vancouver/Victoria where the urban driving and mild weather is attractive. (10,000 sold so far in Canada). I've seen quite a few in my local community as commuter cars. But I don't think I've seen one on a highway yet. (Heck, I've even seen a Segway ridden by a very pudgy city hall worker who looked like he should be walking instead of riding!)
I think the Smartcar is destined for niche and collectors markets like the Mini and Citroën 2CV and isn't going to be a big seller.