Police cars.
A recent thread explores cities evaluaing hybrids. Imagine the savings if there was a hybrid Crown Victoria for police departments? The same goes for Impala's or whatever the GM counterpart is.
I'm not about to suggest every police car should be a hybrid, but the typical patrol car should benefit greatly. An EV mode might be useful in sneaking up on suspects.
This would provide a wealth of experience. I wish Detroit had done this at least ten years ago....