Virtually no one has seen them. I had no idea they existed until I came across the six I have there on eBay and did some research. Check out this site if you want to see more:
http://umassamherst.lunaimaging.com/...vlet/umass~2~2
I came into contact with a professor at the Unversity of Massachusetts Amherst who studies the Inter-Allied Games. He told me that the cards were created by the US Army Signal Corps and there are at least 144 of them covering all sports and the ceremonies.
The set will be in the next edition of my boxing card guide.