My reason for studying rotorcraft has been primarily to understand the limitations of these machine. Compressibility is one limit i do not see as ever being overcome in a rotorcraft. Supersonic prop designs do exist, but the design would seriously hurt the machines ability to hover (mostly through disk loading). Better to find another technology...
Regarding your reverse pitch rotor concept, i gave a similar idea some thought when i was considering Unicopter. It introduces some serious materials difficulties, not least due to the extreme strain leading to fatigue problems well outside the limits of current composites. For a start when did you last see wing-warp ailerons, despite the serious advantages this would offer composite aircraft?
The "Piezoelectric Active Fiber Composite Actuators" are yet only a pipe dream in a laboratory, capable perhaps of small object manipulation. While i suspect the application to rotor blades would make a worthy PhD thesis, it is not available off the shelf nor will it be for quite some time. Good engineering effectively applies the available to the known to push the boundaries of the possible. Trust me, i spend a lot of "thought time" on the fringes, but willingly accept that advanced ideas have to be simplified until they are doable.
The performance advantages are also limited. Although you reduce aerofoil drag, you don't overcome the fact that no dynamic pressure (ie airflow velocity) around the zero velocity circle will result in no lift. This still allows a leak path from high pressure underside to low pressure topside. This is made worse by the fact that either side of this the aerofoil will be stalled. Interleaving will help, although above midspeed the zero vel circles coincide at two positions above the fuselage (ie not too serious). My aversion to interleaving is simply the complexity of drivetrain to keep rotors reliably intermeshed - similar to expensive V-22.
The above all leads me to the final conclusion that you are very hard pressed to beat the outboard advancing, feathered retreating, pusher prop (twinned for yaw control), intermesher - especially if gyro augmented for stability. Coaxial should just be seen as a stepping stone, although N.L. may strongly disagree.
I genuinely don't understand why you seem to have abandoned the (tandem seat) Unicopter concept...
Mart
[Edit: On realisation that reverse pitch aerofoils will most likely be stalled around zero lift circle anyway (ie performance penalty)]