Remember the Morgan 3 Wheeler?
There a company currently building cars that are similar only they use Harley engines. They look pretty neat but they'll probably shake and leak.
Considering gas prices, we may see more of these oddities. The '72 Honda 600 Sedan that I had got about 45 mpg on a bad day. 2 cylinder, 600 cc, air cooled, ran pretty good in a car that only weighed about 1200 lbs.