The Volkswagen L1 diesel hybrid concept created quite a stir at the 2009 Frankfurt Motor Show — which despite a slew of high-end exotics was more green than ever this year. Volkswagen says its one-liter concept car would be the most fuel-efficient car in the world. Actually, they say it is the most fuel-efficient car in the world, but I’ll withhold that title until the car leaves the “study” stage and reaches production.

The L1 is light, thanks to a carbon fiber body; compact like a VW Fox, and short, with a height similar to the low-slung Lamborghini Murcielago, according to Volkswagen. The hybrid has an electric motor and a teeny diesel-powered engine, plus start-stop technology for further fuel savings.

The VW L1 Concept by the numbers:

• 837 pounds
• 12.5 feet long; 3.75 feet wide
• 170 mpg combined

The first car will introduce features that inch the little EV closer to Euro-spec readiness, including left-hand drive. All of the electric Mitsubishis on the road right now in their first phase of testing are Japanese-spec right-hand models, even the few in the U.S. The potato-bug of a car gets a wider stance and longer overhangs for Europe as well.

The i MiEV Sport Air concept is expected to have a more powerful electric motor and a solid driving feel, due to the weight of the in-floor battery packs. It also will feature a “clear cutaway” top, which in Mitsubishi’s sketches looks like a sweep of glass from the windshield to the rear window.

Images courtesy of Mitsubishi.

After hiring out its design arm to create chassis for Tesla and Chrysler’s electric vehicles, Lotus has hinted that it may throw its own hat in the EV ring. The Financial Times reported — and Edmunds.com’s Inside Line passed it along — that Lotus CEO Michael Kimberley said there may be an electric Lotus “shortly.”

According to the Edmunds blog post, “shortly” may be as soon as the Geneva auto show in March. The concept EV wouldn’t be fully functional, but it would give potential buyers an idea of what a 300-mile-range EV from the British sports car manufacturer might look like.

Looking at Lotus’s current lineup, I think we can assume it’ll be along similar curvy lines. And the company already has a tradition of model names that start with E (Elise, Elite, Evora, Europa … ), so coming up with a clever EV name should be a snap.

Image provided by Lotus Designs, from its 2009 calendar. As far as Good Green Cars knows, it’s not the EV Lotus is talking about, but, you know, it could be.