6-18mg/kg. Rabbits have a much faster metabolism them cats, so its best to dose towards the higher end of the scale. Remember rabbits arent the same as dogs or cats. Revolution is super safe even multiple times the high dose.
There is also evidence that the half life of selamectin (the active ingredient in revolution) is shorter in rabbits so they may need to be re-dosed sooner than other species.
I've used revolution on my own rabbits and it is my personal favorite choice for external parasites in rabbits.