This is an interesting theory: Kudzu as biofuel.
Kudzu, for those of you who aren't familiar with the pesky plant, is an invasive Japanese vine that has taken over large swaths of the south. It literally swallows things whole, including trees, telephone poles, etc. in areas where it's allowed to grow unthwarted.
If it really was viable as a biofuel, and we could control it and expand our options for fuel consumption at the same time, it could be an interesting project.
And who knows--get rid of some of the kudzu smothering the landscape these days and you just might find Jimmy Hoffa under there somewhere.
And here's a interesting example of why it's such a pesky plant: http://www.nap.edu/staff/mjensen/aaup2006/kudzu-car.jpg