Ryan,
A rev limiter only prevents over-revs due to introducing large amounts of air (and thus fuel) into the engine, as in too much throttle. The engine needs 3 things for combustion: air, fuel and spark. Eliminate any one of these, e.g. spark and there's no combustion. You're safe.
However, none of the spark-based devices (rotors and electronic boxes) will prevent over-revs caused by an inadvertant mechanical coupling between engine and gearbox as would happen, for example, if one completes the dreaded downshift from 5th to 2nd. If you think about it, this could happen even with the throttle closed, ignition OFF and/or with an empty tank.
For those occasions, you need another product.
Sherwood