Several years ago, Mother Earth News did an article on a homebuilt gas/electric hybrid thats achieved around 75 mpg at normal driving speeds. Dave Arthurs of Springdale, Arkansas, spent $1,500 turning a standard Opel GT into a hybrid car that could get 75 miles per gallon, using a six-horsepower lawnmower engine, a four-hundred-amp electric motor, and an array of six-volt batteries. Mother Earth News used the Arthurs plan to build their own hybrid, which averaged 83.6 miles per gallon. Sixty thousand Mother Earth News readers wrote in for the plans, when the magazine published their results. 1993: Dave Arthur's amazing hybrid electric car - technological improvements from first car built in 1979 - Interview
Mother Earth News, June-July, 1993 by Matt Scanlon

Are there other home built hybrids out there?