eBay do some pretty decent ones actually or you could spend some time checking are the custom plastic sites or even look around miniriders. There is some old topics just like this kicking around.
^^yeah they got some nice graphics and they are different to anything u see around here. Basicly as with everything else it comes down to how much u wana spend. That will determin the graphics u can choose from as they range from $25 (common designs) - $350+ (custom designs).