I saw this from ritrek at the Bitcoin++ conference in Taipei. The RITREK app allows one to pre-sign transactions to move your Bitcoin to a secondary wallet, via 2 transactions with a timelock between them (so that even if something leaks and the first pre-signed transaction is broadcast against your will, you have many days to move the Bitcoin elsewhere before the second transaction can be mined).
It's now live on Google Play:
https://play.google.com/store/apps/details?id=com.ritrek.app
For example, the first wallet can be your hardware wallet + a passphrase, and the second wallet the same hardware wallet without a passphrase.
Then if you lose the passphrase, or something happens to you and your family wants to access the Bitcoin, you/they can broadcast the transactions.