Fuel Efficient Cars

I was reading my favorite blog earlier and came across a diary about current CAFE standards in the United States. Since DailyKos' membership is international, there were several comments from individuals living in other countries with access to vehicles with greater fuel efficiency. Vehicles I have never heard of. Vehicles that are not advertised on my cable stations. Vehicles that I can't purchase unless I leave the USA. Why doesn't my local VW dealership sell the Polo? What's preventing the Nissan showroom from featuring a Micra? And why can I buy a Smart car in Canada but not in America? Earlier this spring while searching for a new car one of my requirements was a vehicle obtaining 40mpg or better which severely limited our options - of course the silver lining in all of this is that the dearth of fuel efficient vehicles led to our grease mobile.