Photos: Ecomodders make fuel good to the last drop

The General Motors Hummer, universally loathed by treehuggers, is notorious for its boxy, high-above-ground design, a main culprit in the model's average fuel economy of only 16 miles per gallon.

However, car manufacturers appear to be shifting, if slowly, toward more efficient, greener vehicles.

The design of the GM Yukon hybrid, for instance, is more aerodynamic than other SUVs. And the Cadillac Provoq concept would get 300 miles on a tank of gas. It features a grill that closes at high speeds to reduce drag. Ecomodders have achieved a similar effect using spare parts from hardware stores and junkyards.