Mercedes-Benz is apparently planning to use next week's Geneva auto show to unveil two new fuel-efficient versions of the C-Class sedan in the first example of a new line of "eco variants" of its main model lineup. According to Just Auto, Mercedes is planning to roll the strategy out to 20 other models over the course of the next year. BMW is also expected to launch a green concept car at the Geneva show. Both luxury German automakers are likely to be among the hardest hit by new European Commission legislation for stricter emissions and fuel efficiency standards, and consequently have been making efforts to find more efficient versions of their performance-focused lineups. At last year's Frankfurt auto show, Mercedes showed off a number of diesel-electric hybrid concept cars that are scheduled for production in 2010 as well as its Diesotto engine, which uses turbo charging, direct injection, and diesel-like compression to maximize power and fuel economy.