Karl, you will be happy to know there is a guy in Kansas who is doing turbo-diesel conversions to hummers and any other big SUV, claims he can make them get at least 50mpg on Bio-diesel. The down side is his conversion costs about $40,000, and that's after you bring him the Hummer you bought, but he says he has no lack of customers. Neil Young (the rock star) is having his 1959 Buick converted to a turbo diesel, supposed to get 100 mpg when it's done. So the question is, why isn't Detroit doing it?