Progress is being made… 😁 
Discussion
I hope you're going to market these when they're done. They look super cool👌🏻.
I’m going to raise a PR to the original project so that everyone can benefit from it.
https://github.com/lnbits/nostr-signing-device
The original code just holds a single key, and signs transactions. I’m adding a load of new features. Hoping to finish testing this week.