It took me years to find my Superman. Even in no working condition, people just seem to hold onto them. Every now and again you see one come up on eBay. They typically go for silly money and then another couple appear shortly after when people think they can get big bucks for them and unfortunately they normally do.
I wonder if Homepin would ever consider a repro of the Atari (in particular Superman) board set. I reckon every owner of a Superman machine would buy one.