I would say about $10k +/- a few hundred (current value adjusting for inflation going forward) for an exceptional modern pinball... That being said, I believe that price would be higher for something that revolutionized the game, and I'm not talking rarity/collectibility, lcd screens everywhere, or custom hand painted art... I mean something entirely different than we've never seen before that adds to and builds upon the current platform... No clue what such innovation would look like, but I feel confident that the potential does exist for someone to discover it. At that point, who knows how much I'd be willing to spend?