Some bikes that have heim-joint shift arms (multiple peice-shift arms) can be switched to a single-peice shift arm and made to be reverse-shift-pattern just by bolting on a different shift lever. Case in point: The RC51.
The RC 51 has a shift lever that bolts to the bottom of the stock rearsets, and another arm that bolts to the shift shaft, then the two are connected by an adjustable rod with heim joints on each end. If you go and buy a Honda CBR1100XX Shifter, it fits right on the RC51's Shift Shaft, eliminating the connecting rod, the shift arm bolted to the stock rearsets and all the joints in the middle..it also makes the bike "reverse shift pattern". Think about which way you are moving the shift arm when you shift up, figure out a way to do the same movement, but make it to where it rotates the shaft the other way, and you'll have a rever-shifting bitch (it's really not THAT cool...difficult to get used to after 15 years of riding )