It is, however, perfectly legal to brew your own biodiesel.
"Well, it's still illegal to distill alcohol at home, something that should have been legalized long ago."
It is perfectly legal to distill alcohol at your home to use as fuel. You do have to get a permit and you do have to promise to denature (add poison to) your alcohol, but you can run a still legally as long as you are making the alcohol as a fuel and not for human consumption.