Bug,
If the previous post doesn't have your head spinning, here is an additional idea that you might like to consider. It's yours to patent if it's any good.
Reduce or eliminate the tail-rotor???
The central shaft is rotating in the opposite direction to that of the mast. In addition, this shaft has a rotational velocity that is 4 to 5 times the mast's velocity.
This shaft could possibly drive a rigid propeller (small rotor) that might counteract some or all of the torque generated by the main rotor.
Dave