Hey Coyote X
Good luck on your project. I would suggest if you haven't seen it yet is the link I am enclosing from the Cornell X Prize team. They have a mule that will be substantially modified, but on their first attempt they only achieved mid 40's. I'm sure your getting much more on your ICE. Weight is a big issue.
Cornell AXP Mule: PHEV Geo Metro - X Prize Cars