How would you like an all-electric wagon with five seats, a rear liftgate, and 187 miles of EPA-rated range?

Sounds pretty good, right? You'd think such a vehicle might sell well, since it would have more rated range than any other electric cars on the market except the Chevy Bolt EV and anything from Tesla.

Well, such a car has been certified by the EPA for four separate model years, since 2012, but it's not formally on sale and you can't buy it.

DON'T MISS: UberX Drivers To Test BYD e6 Chinese Electric Cars In Chicago (Mar 2015)

The vehicle in question is the BYD e6, a Chinese-built five-door with a large battery pack under the floor and front-wheel drive.

BYD sold more plug-in electric vehicles last year than any other maker in the world, including General Motors, Nissan, and Tesla.

But the company is only testing the e6 in very limited U.S. fleet usage, while its U.S. unit concentrates on its battery-electric transit bus and energy storage businesses.

Chinese battery electric crossover: BYD e6 test drive, Los Angeles, May 2012

Chinese battery electric crossover: BYD e6 test drive, Los Angeles, May 2012

We happened to notice that after three model years (2012, 2013, and 2014), the e6 took a hiatus and then re-emerged for the 2016 model year with longer range and a higher efficiency rating.

The EPA ratings page for the four model years shows that the 2016 model has a rated range of 187 miles, compared to 127 miles for the version sold in the first three years.

CHECK OUT: Updated BYD e6: First Drive Of Chinese Electric Crossover (May 2012)

"The 2016 BYD e6 models had the pack capacity upgraded from 60 kwh to a little over 80 kwh," confirmed Micheal Austin, head of BYD's U.S. unit.

Facebook promotion offering BYD e6 electric cars for lease to fleet drivers in Chicago, Mar 2015

Facebook promotion offering BYD e6 electric cars for lease to fleet drivers in Chicago, Mar 2015

The car's rated efficiency also rose, from 63 to 72 MPGe (not that high for a battery-electric vehicle). Miles Per Gallon Equivalent, or MPGe, is the distance a car can travel electrically on the same amount of energy as contained in 1 gallon of gasoline.

Unfortunately, the company declined to tell us how many e6 vehicles it has in circulation in the U.S.

ALSO SEE: BYD e6 Electric Taxi Fleet Launched In Hong Kong To Cut Pollution (May 2013)

Despite repeated questioning, the best we could get out of BYD was the following statement.

BYD has not launched consumer vehicle sales in North America, but has sold more than 16,000 e6s worldwide year to date. When BYD does launch in North America, we look forward to competitive sales figures here as well.

Meanwhile, the company is testing the car with a small number of Uber drivers in Chicago, and e6 test vehicles have been spotted in other Midwest states as well.

We'd observe that when we drove the BYD e6 briefly several years ago, its interior fittings, quality, and materials were not up to the standards of new vehicles sold in the U.S.

Still, for the moment, the BYD e6 may qualify as forbidden fruit: a practical, long-range electric car (of debatable quality and sophistication) that you can't buy no matter how much you might like to.

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