me too larry, especially since my uncle makes his own diesel out of used resturant oil. its around $.50 per gallon cheaper that way.
I saw that process being done on the Spike TV show "Trucks." All of those car/truck shows are basically non-stop infomercials, and this cooking-oil-to-diesel system looked pretty neat, but it would take quite a lot of use to make up your investment -- especially if fueling an automobile which got 40+ mpg on diesel fuel! However, I believe they said the system got the cost down a lot lower than you suggest -- like less than half the cost of diesel out of the pump. Someone with a big diesel truck would obviously get his ROI a lot sooner. But then, you'd have to put up with the constant odor of a french-fry cooker coming out of your tailpipe!