Show the need for other than a Class AB "linear" for amateur service. Isn't that what we're talking about here? All these 'amplifiers' we run are after-market add-ons to rigs that run (do I have to put 'predominantly' here) linear modes. Even CW modes benefits from a bit of 'envelope shaping' to reduce keying sidebands, thereby requiring some linearity in an amplifier. Apparently, there isn't a need for Class C cathode-drive amplifiers; cathode-driven also has inherently have lower gain than grid-driven designs, thereby requiring perhaps another stage in the 'chain'.. The older tube Class C operation amplifiers I've seen for commercial 2-way radio service run push-pull neutralized PA stages at that. One thing- it is easy peasy to incorporate neutralization with P-P grid-driven designs. I don't know what direction you want to take this; I've got a more pragmatic view, one driven from an engineering point of view.