Have you heard of the Kiss system?
I think the holding tank is above the water line and the tank exit and point where the honey-dipper pipe bottoms out is below the tank. Thus, the tank is totally empty when evacuated. Not sure how they handle the pipe from the pump to the input of the holding tank. But that is the advantage of a high tank.... it is totally empty when cleaned out and therefore reduced breeding of smells.
Maybe the ideal is a tank somewhat below the head/pump, but above the waterline?