You should spend some time in Europe. There are diesel 5-series Beemers and Benzes over there. They don't smell, don't pollute, are faster than many gasoline engines over here.
BTW, I'm not a Greenie nor a CAFE advocate. My AC Cobra:
Seriously, I wish someone could make a Cobra (a factory product, not a kit car) with a modern engine. Or something like a Jap XKE. I bet it would sell. But nanny govt. wouldn't allow it because it wouldn't pass bumper and crash tests, I guess.