Reports indicate that Mercedes has acquired 25 patents for lithium-ion battery technology. These are to be used in their new S 400 Blue Hybrid next year. The S 300 model a year later. The general consensus is that they will be rolling out late 2010 or early 2011 if production goes according to plan.
Hybrids in 2008 go as high as $50K now so if you aim for one of these start saving your pennies now.