zeeoo,
A few thoughts about this rotorhead;
A pure Constant Velocity Joint, such as the Rzeppa type, by itself, will probably not work. I do not believe that they are designed to take large axial loads. This appears to be confirmed in the Doman sketches. Here the CVJ imparts torque to the rotor, at a constant speed. However, the other forces are handled by the stationary Universal (Cardan or Hooke's ) Joint.
The sketches and drawings are open to anyone. They are produced as a .dc files in 2D by DeltaCAD, but the program is capable of saving them in an elementary, and imperfect AutoCAD .dxf format.
Regarding your last two paragraphs:
The difficult part is to start off with a full understanding of the subject of cyclical Coriolis and the Cardan Joint Effect. The underlying premise of the Constant Velocity Rotor is that the rotor disk always thinks that it is aligned with the mast. There is no cyclical acceleration and deceleration caused by flapping or teetering because there is no flapping or teetering. The 'rigid' disk (tip path plane) mearly reorients itself in space.
Smaller considerations during forward flight, such as dissymmetry of profile drag, plus flapping within the blade (out of plane bowing) due to the hub spring moment, will result in lead/lag moments. Theoretically, a strong rotor should be able to 'force' its way through these minor 'nuisances'. In addition, the difference between the precone to normal cone angle is intended to help.
Dave