Very interesting car, but I wonder If I ported your engine and put a carby on it I might be able to get you up to 126 mpg if my references are correct.
see
Where I store my results
This forum is where I have started logging my results for my engine.
The reason I say use a carby is my methods really mess up the amount of air and fuel going into the engine eg I have it on video my idling engine using half the normal requirement of fuel an EFI system is going to have a hard time with that, then there is the other end at high rpm its about 50% less efficient but I had the extra power until I cooked my engine.
Mythbusters did a aero test on a car by putting golf ball dimples over the surface of the car I think it went from 26 to 29 mpg, imagine the looks you would get then if your car looked like golf ball surface. I haven't a clue on how you would press the dimples into your body panels though.