Toyota leads the world in hybrid-electric vehicles, having built well over 2 million of them since 1997. That's more than half the hybrids on the planet.

Now, with new electric cars about to hit the showrooms--the 2011 Nissan Leaf and 2011 Chevrolet Volt, for example--Toyota wants to cement its leadership by licensing out its Hybrid Synergy Drive system to other carmakers.

The latest to join the growing list--perhaps--may be the most unlikely: Mercedes-Benz, which is rumored to want Toyota hybrid technology for the next generation of the A-Class subcompact hatchback it sells in Europe.

The 2010 Toyota Prius

The 2010 Toyota Prius

According to Japanese newspaper Nikkan Jidosha, quoted by Reuters, the two companies are negotiating for a supply deal that would start in 2013, when the A-Class is competely redesigned.

Toyota first licensed Hybrid Synergy drive to Nissan, for the limited-production Nissan Altima Hybrid it sells in only a handful of U.S. states. Last year, Nissan sold 9,357 hybrids, while Toyota managed to shift fully 173,655 hybrids in the U.S. across all its lines. No threat there and, besides, Toyota probably limits Nissan to 10,000 systems a year.

Then came the news in March that Toyota would license its hybrid system to Mazda, which had previously sold a Ford compact SUV hybrid model as the Mazda Tribute Hybrid. But Ford sold most of its stake in Mazda during the economic crisis, so the Japanese maker of 'zoom-zoom' sporty cars is now looking further afield.

Subaru, too, is expected to use at least some elements of Toyota's Hybrid Synergy Drive in a Forester Hybrid model that will arrive in the U.S. in 2012. Toyota owns roughly one-fifth of Subaru's parent company, Fuji Heavy Industries, so that's not a surprise either.

Mazda Tribute Hybrid

Mazda Tribute Hybrid

But the Daimler connection is. If anything, it's a testament to Toyota's expertise--especially since Mercedes-Benz and BMW are working together on their own hybrid and plug-in hybrid systems for their midsize and full-size luxury sedans.

It may be that the Toyota system will be limited solely to the A-Class (which was also just launched in a limited-edition all-electric version), and Daimler didn't want to go to the expense of adapting its larger hybrid system to front-wheel-drive.

But here's the funny part: Daimler owns roughly 5 percent of Tesla Motors, through a 2009 investment before Tesla went public. More recently, Toyota took a share in Tesla, which is developing an all-electric RAV4 crossover for it, to be revealed at this fall's Los Angeles Auto Show.

So is it true what they say? Do all roads really lead to Tesla?