Got the print from Shapeways today! The whole cube is much sturdier than I expected. I wasn't expecting quite such a coarse finish when ordering "Polished and Dyed", but it's less visible to the naked eye.
Doesn't quite fit the orange of my board. Unfortunately, there is some variance to the dyeing process SW uses, so that's to be expected.
With switches and keychain QD installed. Switches fit in quite well, but because SLS 3D-printing isn't perfectly repeatable, one of the sides has a looser fit than all the others. It still seems like there's no way for them to fall out accidentally, but if I were to mount very valuable switches in there, I'd probably hot-glue them just to be on the safe side. I'll keep this in my pocket the next few days to see whether they come loose on their own.
I'm not feeling comfortable posting the link to the SW item here, after all this isn't my IC. If you want one, googling "FidgetKeyCube" should be sufficient to find it.