Vespa's South African division had this stretch scooter made as a promotional gimmick. They refer to it as a family-sized vehicle:
According to Vespa, here's a list of uses for the stretched scooter: it's a sensible family car on two wheels and kids will look forward to going to school on it. You can be the designated driver and still park outside the front door of the party. When you make new buddies, you can take them home with you - and you save money on fuel.
It's a custom job, so don't rush down to a dealership expecting to find one.
Link via CrunchGear
A small to midsize motorcycle will have no problem getting fifty miles to a gallon, and they get to skip the "Gentle Run" part of the equation. On a loaded touring Harley I have seen people get upward of forty miles a gallon, once again without having to hold back. My girlfriend's small, 35 year old Honda gets easily seventy or eighty miles a gallon around town. My larger, 40 year old Honda gets somewhere around fifty or sixty without sacrificing rapid acceleration.