These are a couple videos of the custom 'levitating' Star Wars speeder bikes built by Lithium Cycles using electric bicycles from Super 73. Obviously, they're not really levitating, they just have mirrored fenders that cover the wheels to give the ILLUSION of levitation. Still, very clever, and if I were judging the costume contest they entered I'd definitely have no choice but to tell them they tried way too hard just to win a $75 gift certificate to a place they don't even like to eat.
Keep going for two videos, the first of the bikes speeding around New York City (complete with chase), the second documenting the building of the bikes.
Thanks to Phil F., who agrees they really missed the opportunity for some uproarious Ewok hijinx.