Dave,
I agree with Mart about keeping design simple. Two blades is simple, partly the reason for the large sales of Robinson compared with Enstrom and S-300 with the complication and cost of three blades.
Mart,
The Yamaha RMAX is more than a model( at 128lbs). It has also carried a videocam, no reports of vibration on the camera. More than 1200 have been sold mostly for crop dusting by non-pilot farmers in Japan. It has automatic hover. Pretty impressive.