According to Wikipedia, this model was a failed experiment as it is no longer for sale:
The Smart Forfour was a supermini produced by Smart from april 2004 through june 2006. Unlike the other models of the marque, the Forfour was a more conventional five-door hatchback with a relatively roomy interior, available as a four- / five-seater. - Wikipedia
Then again, there is probably the possibility of a return for sale in the US if Smart becomes a hit there.