I think the ultimate solution is a dead man's switch that is tied to something physical, aka a password in a bank vault that unencrypts a file somewhere. Yes, you have to trust the bank, but it's unlikely the bank knows what to do with this random password.
This is what I do - all my passwords and super-secret stuff is in an encrypted file with the passphrase something I have memorized. It's also written down and stored in a secure location that my wife has access to, should something bad happen to me. I don't care if she accesses this password when I'm not dead - it's only in a secure location to prevent accidental disclosure (theft) of it.