You’ve debated getting an E85 FFV and read up on what it would take to convert that old diesel into a SVO vehicle, but have you every considered scooping chicken poop into your car? Harold Bate did, in the 1970s, and there’s quite a few good Internet resources telling his tale. One is at Journey to Forever, and it starts with the text of an article from Britain’s the Enquirer newspaper. Apparently, there is also a movie about Bate, but it's difficult to find.
The basic gist of the Enquirer article is that it is possible to use the methane from chicken feces to power an automobile, although 30 years ago the British Ministry of Transport said there wasn’t enough supply for everyone to drive a chicken-powered car. Nonetheless, Bate’s idea – taking a waste material and turning it into energy – is very much in line with hybrids (taking braking power and turning it into electrical energy) and homemade biodiesel and SVO (often taking used restaurant oil and using it to run a motor).