The closest thing I've seen to a real-life Mr. Product has to be the WB Girls. This was a series of plush toys and other merchandise created for the Warner Brothers mall stores back in the '90s, featuring charcters who were themselves girls who shopped at Warner Brothers stores. Conceptually speaking, it has a kind of mobius strip quality that could drive you insane if you think about too long.
Since then this kind of cross-trademark cannibalization has gone mainstream, resulting in products like the Barbie Loves Tweety Bird doll:
The next step, of course, will be a Barbie doll that collects Barbie dolls. If they can figure out how to get Barbie to pay for her own merchandise, maybe they can finally leave the rest of us out of the whole thing.