I don't know that my Banshee has ever hit a rev limiter. It does stop pulling at max rpms, but I just figured that was limited by my pipes, stroke, fuel/air ratio, etc. If we have rev limiters, I would like to know as well.
I bought one (from SRP) for my YFZ that was supposed to increase rev limit by 1000 rpms, I can't tell much difference, but I'm sure its there.