[RobertSmalls]

Ah, here's the study from Dr. Samaras that I was thinking about. http://solar.gwu.edu/index_files/Res..._for_PHEVs.pdf

Here's a Green Car Congress digest of the paper:

Green Car Congress: Study: Meaningful GHG Benefit from PHEVs Requires Low-Carbon Electricity

@Neil: I have addressed each of your points in my OP.