Thanks, Bandonov and NeoDragonKNight!
Making the cardbacks took a while, but mostly for the image manipulation and labeling process. Making the physical cardback was relatively simple: I printed the finished image for the cardback (front and back, with filecard, etc.) in photo quality paper, and then used a spray adhesive to stick them to a comic book backing board. I used a rubber crafts roller to go over them a few times, to make sure there were no bubbles. Then, I used a circular blade trimmer to cut the board to the right size, and scissors to round the corners.
I bought 5 "repro" figure bubble blisters from a guy on ebay (there are actually quite a few suppliers, and at the time 5 was the minimum order). I could have made these myself, but I didn't want to mess with it--I didn't have a shop vac at the time, nor a set up for vacuu-forming. Buying them was faster and much cheaper.
Then I needed bubbles for the accessories. I couldn't find these for sale online, so I took them out of two carded Funskool Joe figures (which at the time were plentiful and cheap online). I cleaned any remains of coloring and cardboard from the accessory bubbles, and then used a strong paper glue to stick on "lip" of each bubble to the appropriate place in the card back, and a weak glue stick to stick the other lips (so that I could open them at will without causing damage).
If you want to know how I came up with the images, let me know. It'll be a long post, but I will be happy to tell how I did what I did, and what sofware tools I used.
By the way, here is the image of one of the card backs, including the filecard I wrote (based on the 3 first movies, and the Young Indiana Jones Chronicles TV show).
