Something like this would be fun. I personally like your suggestion of names Old Tele Man. Ultimately ending at the title of Hypermiler would be a privilege. Plus, for those that are below EPA, having a title for that too is a good idea. I might add, perhaps the color could change too. Red for Below EPA and ending with dark green for hypermiler. Course, yellow, a color that would probably come in between the two extremes, might be hard to see on a white background.
Oh, and Extreme-miler and Ultra-miler might need to be switched??? I don't know, when I think of extreme, it's pretty extreme!