We want to obtain one of the new Smart Cars that are selling in
Europe. We know that they will not be imported for sale in the US for
a couple of years. We would like to go to Europe (Germany, Denmark,
Sweden, etc.)this summer and buy and use a Smart Car. May we bring it
back to Massachusetts in the US and drive it legally in the States
after we have owned and driven it abroad?

See if this helps: 
<http://answers.google.com/answers/threadview?id=289678>

However, there could be a simpler solution. There are other
regulations for vehicles imported from Canada and "From the 4th
quarter of 2004 smart will enter Canada as the first market in the
Northern part of the Americas. At first the smart fortwo coup?  und
fortwo cabrio with cdi-engine with the innovative
three-Liter-technique or ???60 miles per gallon vehicle? will be
presented. Sales of the first models in Canada will go through the
existing Mercedes-Benz dealer network. This decision was announced by
Marcus Breitschwerdt, President of Mercedes-Benz Canada, at the
Canadian International Auto Show in Toronto." (SOURCE: Viva LaCanada,
http://www.vivelecanada.ca/article.php?story=20040324203218409>).

Smart Canada Site
<http://www.thesmart.ca/>

Two organizations - JK Technologies of Baltimore and Smartcar USA
(selling through ZAP http://www.zapworld.com/new-cars.htm) are
claiming Fed OK to sell Smart fortwo certified for the USA beginning
in late Summer 2004.  JK is taking non-binding reservations for brand
new glass roof and for cabrio Smarts.  My understanding is that they
will be "fully loaded" with accessories and be about $18K and $20K. 
They also state they are arranging service locations across the USA. 
Mercedes seems to be still keeping their head-in-the-sand and will
encourage Mercedes to ignor any so-certified Smarts.