This is awesome! I have no use for this but it's great that you can do this to help others. A couple years back I had an issue with my original Duo hu-card lid and I was able to trade with someone (here, I believe) to get a replacement. Now, it might be harder to get one. It's cool that you are working on those next.
I've also been working on my 3D modeling skills, so outta curiosity, what software are you using? And which 3D printer? One day I would like to be able to make custom board game pieces for mockup designs doing something like this.
