[kelnos]

I guess the Android SDKs are "open", but if you want to do anything lower-level, or be able to upgrade the Android version later (at least for more than just a few years), you need it to be a lot more open than pretty much all Android tablets.

I think the sibling's suggestion of a Raspberry Pi with touchscreen is much better from that perspective, but then you're on your own for building a polished "product" around it, which is unfortunately more involved than just 3D-printing a case for it.