Can't say I've made one, but I'm curious--how are they getting used?
Just to sort of throw something out there, I could see putting together a playlist of 75 Miku songs (Bingo numbers
apparently go to 75, with a range of 15 under each letter.). You use those songs to make enough cards for you and your fellow Miku-philes, and then you get together and have your MP3 player (or a YouTube playlist, if you prefer) play the playlist at random so it "calls" the songs for you.