I know of a place with well over 100 EM pins....another collector with at least 40 plus pins and 60 plus arcades. Additionally I know of easily 10-20 collectors/hobbyists with collections ranging from 10 to 40 plus games. And I am not including business that sell games. I would say there are plenty of collections similar throughout the US or other countries. I think what would be good is to capture not only some amazing collections but facts and history on the development or significance of each game.
All of these people collect for various reasons so it would also be neat to learn about these individuals as well. I am very greatfull to have many of them as good friends and they are always sharing their amazing collections with friends and helpful to others. That has been my experience. They are passionate and are preserving a piece of history that otherwise would be lost.