Actually, ELECTRIC drive blows Diesel away, even in the low end... which is exactly why DIESEL-ELECTRIC is how every large vehicle is built.. whether it be Railroad or Earth Movers, and why Diesel-electic should be applied to things like Busses and such, and is being used in test cases around the country now.
Right, because electric motors have a flat torque curve - the produce the same amount no matter how how fast it spins. People who buy gas-electric hybrids for MPG are actually buying them for the wrong reasons. Their purpose is actually to reduce emissions. Somewhat better MPG is a happy coincidence because the electric motors allow the use of much less powerful gasoline engines.
At any rate gas-electrics are the answer for now to balance emissions reduction with improved fuel economy.