I thought about this some more. It won't work because when a class method
is called via super(), 'cls' is still set to the derived class (and in
general for class methods that's the right thing to do, just as it is for
regular methods that self is still the actual object). If you read my
previous long comment you'll understand that all the __subclasshook__
methods carefully return NotImplemented immediately if their 'cls' argument
is not the class where they are defined. So it won't work.

I also don't see the use case (you're not supposed to do this at home,
basically).