I was a home-brew doubting-thomas (but definitely running into runninng 100% BioD), but $.43 a gallon is a strong incentive to try a DIY bit of brewing. But an oil analysis would be a better argument, check out that thread and see if you'd be into testing that old engine oil. If there is a lot of left over glycerine or gunk in your homebrew, the oil analysis should show some serious iron as the hard-to-burn bits glaze the chamber and increase wear. This is what discouraged me from a SVO kit (even though they have a nice, slick invisable option at
http://www.goldenfuelsystems.com/Jeep%20Liberty.html).
If your oil turns out OK, I'll pour homebrew in mine. I have plenty around, but I use it in the furnace and pay quite a bit for commercial grade stuff for the Jeep. Still waiting on my oil analysis for the next change at 18k miles. You show me your and I'll show you mine..
-Paul