My initial research has been focused on a few key things.  First, I’m looking at manufacturers.  There are many options out there when it comes to manufacturing playing cards.  Here’s what I’ve found so far-

https://shuffledink.com/ – These guys do custom cards of all kinds as well as board games.  I’m not trying to make any board games just yet, but have thought about that as a next logical step.  They do production samples for $50 and are based in Florida.  They’ve also got a blog about making a card game from idea to product – http://blog.shuffledink.com/.

https://www.4imprint.com/search/playing%20cards – These guys appear to do various “semi-customized” promotional items of all sorts.  Looking at their playing cards, they only seem to add logos to their existing card decks – not what I’m looking for.

https://www.customplayingcards.com/business.htm – This company does custom cards of various types.  I can’t tell exactly from looking around their website if they will meet my needs, so I’ll have to reach out to them with some questions.

http://www.printerstudio.com/unique-ideas/custom-playing-cards.html – This place has what I want at $5.20 per deck if I order 500 decks.

http://www.bicyclecards.com/custom-printing/ – Well-known brand of playing cards – turns out they print custom decks too.  No info on their website other than a minimum order of 1000 decks is needed for custom projects.

https://www.thegamecrafter.com/ – This is another company that does complete board games.  Playing cards are included in their product offering, and they also have an online store where you can sell your games.

http://www.usplayingcard.com/customcards/ – Little info available on the site, but this is another company that will do custom cards in large runs.

http://card-press.com/ – Their website was missing several images when I went to it, but we all have bad tech days, so I’ll look past that for now.  I can’t tell from the site if they do custom printing on both sides of the cards, but will send them a note anyway.

http://www.makeplayingcards.com/custom-print-game-cards.aspx – These guys look to be a viable option.

Apart from identifying some potential manufacturers of the cards, my research has also started my education on card games and paper.  There is an acronym “GSM” which stands for “Grams per Square Meter” which is a measurement of the quality of the paper.  300 GSM appears to be the lower acceptable standard for playing cards and 310 GSM is the premium grade.

Here’s a short description of paper ratings (all of the playing card companies seem to use GSM, even in the US). http://creative.uwp.edu/page/paper-grades

Second, I’ve been playing the game with anybody that will sit down for 20 minutes and play with me (mostly my kids).  We’ve been refining rules and cards as we go and I’ve started a pile of bad ideas that are the “reject” cards we no longer need after a rule adjustment or new idea comes in.  I’m keeping all the rules in a Word doc and keeping track of changes and new rules as we go.  This will come in handy later on when it’s time to write the rule book for the game.