If you have any ideas, please share! Design is not my strong suit.

I was thinking maybe some surface features, like craters (in silkscreen) and some "resources" -- tinned exposed copper / copper covered by solder mask.

Or some way to hold the boards together, like a magnetic clasp or even just velcro. It's not really a problem presently, but might be neat.

I think getting a good designer onboard has the best chances of taking it to the next level.

Yeah, that's a good point. A colleague did offer to help, and then donate the results to some schools. I'm not sure why it didn't occur to me to just say yes!