I found this on eBay. It's a vintage UofL jacket. Check it out here. It made me laugh, because the description for the item reads: "THERE WAS A GROUP OF DENNY'S FRIENDS THAT ALL HAD THESE JACKETS, THEY ARE VERY COOL & YOU DO NOT SEE THEM VERY OFTEN." So, one of these hypotheses must be factual: Denny Crum made jackets with his face on them for his friends. Denny Crum's friends made jackets with his face on them and referred to themselves as his "chums." There are not many of these jackets out there because he did not have many chums.