There should definitely be a gemach for Stanley cups. Some of us go hiking or on other outings during the summer months and it's humiliating to be seen in public with an ordinary water bottle.
You can't get a Stanley Cup by buying it or through a gmach. You have to win it in the Stanley Cup Finals, and even so, after a little while you have to give it back to the Hall of Fame. Once you do, you get a smaller replica that you can keep. Doubtful that anyone so honored would give it away to a gmach or even rent it out.