Josh on Nostr: Love the idea. The replies above have the USB side covered, so the bit I'd add is ...

Love the idea. The replies above have the USB side covered, so the bit I'd add is that even a proper hardware key like a YubiKey has gaps for Nostr, no say in the entropy, no seed backup, you can't see what you're signing, and the PIN goes through the host.

That's what I've been building the Favilla KEY to fix. Entropy made on the device, seed words for restore, QR so you read what you sign, PIN entered on the device itself. Your instinct is right, it just needs hardware made for the job.