Yes, I had researched WVO years ago, I have always stayed away due to the current warranty issues I've had with Ford, let alone taking it to the dealer powered on french fry oil.
Also recently "The Man" is making their way to locking down most local restaurants. When this fad started restaurants had a hassle of unloading this used oil, but like anything once it got popular businesses started up and are taking all of the WVO from these kitchens and processing it on their own and the average guy can't show up and take the fryer oil anymore.
If I were to do anything I would make my own bio that can be added to my current tank. I have researched this and it looks fairly simple if you have some time and a place to play Mr. Wizard. I wouldn't do it unless I would spend some time whipping up 100 gallons at a time. This would last me approximately 1 month and the price to make it yourself is approx $1.60 a gallon with an investment of about 2-3K to get started. Guessing $4 a gallon and investing $3k, break even is 1250 gallons. Is it worth it? probably. Am I going to do it? probably not.
If you can make your own for 1.60 I'm curious where the bio diesel guys get off charging $4.66. Are they taking advantage of tough times as well?
I for one think this economy needs to capitalize on these alternate diesel fuels, not for me (but it would be nice) but for the 18 wheelers. When their prices go up, we pay more for all of our goods.
probably one of the better sites I've read about alternative diesel fuels.
http://journeytoforever.org/biodiesel_make.html