Pete, it appears that you have vehicles that are designed to use high concentration ethanol. Ford has been a pioneer in ethanol powered vehicles. Many vehicles don't recommend using fuel with ethanol content over 10% for a variety of good reasons. Ford has been a pioneer in alcohol fueled vehicles.
In some instances at least, it it appears that ethanol production may take more petroleum to produce per gallon than it makes!
Interestingly, one can infer that an engine optimized for alcohol (very high compression due to the high octane rating) could also be suited to natural gas usage given a suitable fuel system.
It is worth reading the articles on Flex Fuel Vehicles and ethanol fuel in Wikipedia (among others I'm sure) to see the current state of the art.
Depending on the ethanol study you read, net energy returns vary from .7-1.5 units of ethanol per unit of fossil fuel energy consumed. For comparison, that same one unit of fossil fuel invested in oil and gas extraction (in the lower 48 States) will yield 15 units of gasoline, a yield an order of magnitude better than current ethanol production technologies, ignoring the energy quality arguments above and the fact that the gain (14 units) is both declining and not carbon neutral.
Cheese Heads will welcome the info that the whey from cheese production is also an excellent raw material to make ethanol.
Unfortunately the lack of net savings in oil consumption and the strain on corn production raised the price of transportation fuel an the cost of corn-based/fed food ($8-$20 steak!!!) and perhaps other grains as well. But what is the footprint of sugar-based ethanol, such as in Brazil? US sugar beet growing states need an economic boost, why not sugar beets for alcohol?