It's a great idea, I've been working on some similar products but in the end it always comes down to the fact that if you give someone the private key to etch/engrave/print, it's not secure. If you password protect it, it defeats the purpose somewhat of having a backup.
Hard to imagine a way around this before 3d printers take off.
You could write down the password in a way that only you would understand, then laminate that and stuff it in a magazine in your attic. Even if someone finds the password paper (which they won't) they won't understand it anyway. And as if a common street thug who breaks into your house is even going to care about stealing this thing that looks like a paperweight.
Yes, but a bulk of the reason behind these types of 'backups' is that in the event you're hit in the head, in a coma, or more realistically: forget your password (old age, not using the password for years, etc) you can still get your BTC. If you have to password protect it, you're still at risk for losing everything.