This can play with your head,
I assume that the max pitch is a fixed angle. The motor does very small pulses per revolution at the appropriate azimuth thereby deflecting the blades equal and opposite to the max pitch. In a 'steady' hover the poor little helicopter will be copping four spurts from the engine which is then transfered through the fuselage..... On a full scale helicopter, the pax would be feeling an extremely uncomfortable 4 per bounce. It is only the fact that RC's have a relatively higher RPM that it may be acceptable.
Dave, the blade system wouldn't need to be a 'rigid' head as you described. The way I have come to understand it in my head....(read that how you will)..... the head would be a teetering head, similar I guess to an old 47.
Cheers