There are two diesel hybrids in the works. The some-what more conventional of them is coming from an Indian automotive producer. Arriving in 2009 first as a standard diesel, the 150hp pickup will be followed by a diesel-hybrid version in 2010.
The less conventional of the two US options is a kit car from Robert Q. Riley Enterprises, LLC. According to the web site:
The XR-3 Hybrid is a super-fuel-efficient two-passenger plug-in hybrid that achieves 125 mpg on diesel power alone, 225 mpg on combined diesel and electric power, and performance like a conventional automobile. . . . At just 1300 pounds, this high-performance design combines lightening-fast acceleration, a maximum speed of 85 mph, and fuel economy of 125- to over 200-mpg.