Re: Who is ready for the next level?
Issues to consider:
Weight and Room.
Adding an electric motor and battery along with a 48/66cc motor kit would reduce the efficiency of both.
Trying to add yet another part (gen) it would be a big heavy crowded bike even if you could get it all to fit.
Now towing a trailer with a solar panel and charger to charge the battery when it's in sunlight might be feasible though and far less taxing on both motors.
More miles per $ vs Performance.
Seems to me the only way you can make both motors perform at peak efficiency would be to always be using both motors at the same time, even then you have the same weight and room problem but if you want a new challenge then there you have it, design an automatic electric motor controller that senses gas motor RPM and matches the electric to it ;-}
As for a bike generator to charge a big electric motors Lithium Ion battery pack forget it unless you plan to use some 11HP Morini type motor because trying propel you and all the weight AND a generator power draw you'd drop even high performance 66cc 3HP 2-stroke to its knees and you can't charge a LithIon battery while it's in use anyway.
Just my off-hand thoughts.