Just saw this and felt like you might be interested.
NYC has just begun testing a new bus. It has an all electric power train, with a small gas turbine powered generator supplying the charge along with regenerative braking. Seems like a similar system to the Volt.
An advantage is that because of how efficiently the turbine runs, the exhaust is cleaner than a standard diesel bus without the need for any exhaust gas treatment.
Very cool.
M.T.A. Tests Sleeker Bus With Turbine Engine - City Room Blog - NYTimes.com
[ame=http://en.wikipedia.org/wiki/DesignLine_International]DesignLine International - Wikipedia, the free encyclopedia[/ame]