one like this?
MOTORISED BICYCLE 80CC/MOUNTAIN/TRAIL/POCKET/BIKE MOTOR - eBay Mountain Bikes, Bikes, Cycling, Sport. (end time 08-Oct-08 22:18:16 AEST)
its not quite a whippersnipper motor but you get a choice of 50cc and 80cc. you can get it cheaper elsewhere, at my work i think th motor kits are about $250 or $550 for the whole bike and motor assembled. after run in you get about 60 - 70 kmh outta them.