DETROIT – On a sub-freezing day during the North American International Auto Show here, Mini unveils a concept car called the Beachcomber, featuring a removable roof and detachable doors for open-air motoring.

“It’s for the person who likes the great outdoors,” says Ian Robertson, a board member of Mini’s parent company, BMW AG. “We’re exploring if this is another niche for Mini.”

If it goes into production, the funky 4-wheel-drive car would join an expanding lineup that includes the original Cooper S, a convertible and extended-length Clubman. Coming soon are a coupe and roadster.

Robertson declines to name a number when asked what, on a 1-10 scale, are the Beachcomber’s chances of becoming a production vehicle.

“We’ll have to gauge the opinion of people at this show and others, but we have a reputation of showing concepts and then building them,” he says at the car’s world-debut. “We’ll see more Mini versions coming to market. We have a lot of ideas.”

The original U.K-made Mini dates from 1959 to 2000. BMW’s modern version hit the market in 2001 and has gone on to do surprisingly well, especially in the U.S., where more units are sold than anywhere else.

“We didn’t expect the U.S. to become the dominant market because Americans tend to like big cars,” Robertson says. “We’re proving you can sell small cars here.”

Worldwide, Mini sold 216,500 of them last year, a 6% decline but a relatively modest drop compared with the rest of the premium small-car segment. U.S. sales totaled 45,000 in 2009, a 16% drop.

In a test program, about 600 electric-powered MiniEs are on the road in the U.S., Germany and the U.K.

Touted as the world’s largest EV car fleet, consumers have leased the cars for six months. Mini is extending the lease program to another half-year in May.

The auto maker currently has 90 dealerships in the U.S., most associated with BMW outlets, “but we have always made a clear brand distinction,” Robertson says.

About 10 more dealerships are planned this year in metro markets lacking brand representation. That includes El Paso, TX; Raleigh, NC; Allentown, PA; and Tempe, AZ.

BMW dealers are most likely to get new Mini franchises, “because we already know them,” Robertson says.