It's been going on for quite some time now. Individuals with time, money, and a whole lot of patience are importing Smart Cars into the U.S. It's supposed to be illegal to do so, since they don't meet DOT crash-worthiness, equipment, and EPA evironmental regulations (actually, they meet the regulations, but the DOT / EPA has to smash the cars themselves to believe it), but apparently it can be done.
Here's the classic story about Sally Jesse Rafael and her green Smart. It's not for the faint of heart.
Here's another guy who's got a Smart Cabrio, complete with ugly custom paint in NYC. I think his was imported in parts (legal, ish) and then assembled here. You can also buy one from these guys (caution, bad website alert) in Florida. The prices aren't even that high, $14,700 for the coupe
The Smart Car stable has been getting bigger as of late. But the looks of the cars has really gotten worse in my opinion -- the Smart "forFour" is particularly hideous. The roadster and roadster coup are better, but really depart from the cute-city-car design of the original Swatch/Mercedes joint venture.