Harold Benich's biodiesel Harley-Davidson Fat Boy can get up to 115 mpg, and regularly gets 80 to 90 mpg (my quick Google search tells me that standard Harley's get somewhere between 20 and 50 mpg, depending). Benich says he plans to make and sell a limited number of the biobikes starting next year for between $29,000 and $40,000.
Carl Vogel's electric bike can go about 60 miles on a charge (traveling at 55 mph) and is recharged in about three hours. For longer trips, Vogel can hook up a modified sidecar, which houses a biodiesel-fueled generator that recharges the batteries. The generator also takes straight veggie oil. The EV Harley doesn't make that loud rumbling sound, but it certainly makes green bikers' hearts go pitter-patter.