The ridiculously efficient diesel engine was forbidden fruit to those of you south of the 49th...
I had a chance to drive one of these a few years back:
Slowest car I've ever driven, yet still entertaining (al fresco component had a lot to do with that).
Also ridiculously efficient:
Test drive: Smart Fortwo diesel cabriolet - saw 67 mpg US (in 100% city driving)
Highway rating is: 4.7 L/100 km (51 mpg US)
Ad says they're parts cars, but one is complete: