I'll put it this way -- I didn't make backups until my 2nd round of sales. But I still have that Sonic and a few other protos, inc. Cyborg 009. I guess if you want to count backups I might actually have about 6 of them.
I only wish I'd have backed up Tsubasa and a few others, including those unreleased games. I do know they went to a good collector, so they're in safe hands. :) I always feel good about that.