Turns out one of our readers is an Iron Butt rider with a modified 50cc motorcycle. Bob Munden took a stock Honda NS50F, modified the fairing for better aerodynamics, and repainted it for good measure. Nice work, and that red paint is a lot more attractive than the stock "Barbie Bike" look, as Bob calls it.
The NS50F was a street-legal version of Honda's NS50R race bike, which lacks the lights but has disc brake and alloy wheels. Otherwise I think the two bikes are identical. Both share the water-cooled 50cc reed-valve engine and six-speed gearbox.
Check out more photos of Bob's bike here.