I doubt smaller engines would do the trick - as everybody knows small engines are weaker than their larger brethren. A weak engines doesn't produce much torque and as such must have lower gear-ratios and spiky torque-curves at low revs - the Ford KA is a good example: it produces maximum torque at 2500rpm. However, a car with a larger engine, say a Volvo S60 2.4, will have more power. Because of the extra power, the gearing can be taller, and peak torque can be produced at higher revs, without ending up with a curve resembling a mountain.
The larger engine will also be less stressed than the smaller one. What many people seem to miss - especially politicians - is that stress results in polution. I have no idea what the avg. polution ratio is here in Europe, but I do know that the Suzuki Baleno 1.3 polutes 45% above average, and the Volvo mentioned above 25% below (numbers are rough, don't remember exact values). For those who like to talk about pollution from cars, why not argue those numbers instead?
I don't believe in electrical vehicles either - because if the car gets its power from a nuclear power plant, the car is essentially nuclear powered (now there's a thought!).
Hybrid cars are a good start - but diesel cars with particle-emission filters pollute less and more fun, plus you get the same mileage and diesel costs less. Personally I believe in hydrogen-powered cars. Seeing as how BMW and Mazda have converted conventional engines to run on hydrogen. Even though lubrication is necessary, it's a step in the right direction. Plus they can get three times as far on a full tank compared to a conventional car.
There's only one backdrop I can think of hydrogen though (any type): what happens with the water during the winter?
