Expensive wooden chess sets sometimes include extra queens (1 White, 1
Black), allowing you to properly enjoy famous games that had four queens
on the board. The Alekhine - Capablanca WCC Match had one such game.
Doug, I have always wondered why limited promotion rules became popular at
the same time as chess playing computers - which have no difficulty in
putting any number of queens on the display screen. As for your 'rule
reversal', King and Pawns endings would become pointless.