That does change things.
I'd head the list with the Geo Metor XFi; 45 MPG if you follow the green Eco-light indicator on the dashboard.
Then the VW Dasher [diesel]; it was rated from the factory at 36 MPG, I have one with a five-speed conversion and I've gotten 45 MPG with it as well.
It's looking for a good home. It's driveable but not streetable. The tags are expired, but I need to find an Oregon buyer because it has Pacific Wonderland plates. Hmm, maybe I could get the plates transferred to a different VIN?