Wow, very creative! I know it's not the cheapest way to do it, but MooCards.com makes it really easy to print sets of unique business cards (like each card in the stack has a different design) - that might be a fun way to 'make it real' with cards he can play with his friends if he manages to get a league going at his school or something!
Thanks for the tip about moocards, we will look into it.
I printed out the files at work for him on paper, and used the paper slicer there to make the cards. Scissors also work of course. My kids are playing with 5 decks right now, and that seems to entertain them.
Great work Gregpilling Jr, keep it up!