No reason for this to be a joke. I saw this product in Popular Science about 8-10 years ago, when I had a subscription. Seems like there's a pretty narrow market for something like this- lots of higher-end 35mm cameras are already compatible with newer digital bodies, and people shooting with new-but-vintage 35mm cameras (like the ones that
http://usa.shop.lomography.com/cameras Lomography sells) want film as just one component of the overall aesthetic of shooting those types of cameras.
Still, though, I wouldn't mind playing with one of these. It would cut down significantly on my film processing costs!