The ScubaPro warehouse in Hawaii used to be an eddy point for all kinds of odd stuff. They had literally boxes of the handpainted G250 covers. Once you bought one and realized the paint would wear off, we just went ahead and stripped the paint off to start and had clear covers.
Of course then we had to fashion accessorize the diaphragms since they became visible. Now they have clear diaphragms apparently, but then they only had blue, black, and red.
EDIT: The more I think about this, the more I want a clear second stage with a clear diaphragm. It would be such an awesome thing to use teaching.
I stopped using ScubaPro long ago though, so, so those are long ago stories. If you know someone who owns a shop in Hawaii, I bet those boxes of hand painted second stage covers are still there at the distributor warehouse though.
Maybe ScubaPro Hawaii discovered eBay and managed to clear out the oddball junk from their warehouse though.