It's been rumored for quite some time that automotive companies have kicked around a diesel hybrid.  Its now much more then rumor according to leftlane news.  The VW Golf Twin Drive is going to be limited in Germany right now where they will produce 20 for the German government.

The electric motor is rated at 82 horsepower, and when its energy is spent, a 122hp 2.0-liter turbodiesel engine kicks in to extend the range.