I've read reports of good results using a two tank system, and a heated fuel filter with clean vegetable oil... (Warm up the engine using diesel and switch back to diesel to purge the pump of the thicker oil before stopping)
Here in the UK you can use up to 2500 litres of veg oil annually without paying, or even registering for payment of duty. So I could potentially make a 30% saving each time I fill up - at the price I would pay for veg oil in a local supermarket!! Buying it wholesale could increase the savings a lot more!
I'm seriously thinking of trying it out...
