~snip~
also i would like to suggest a 2 of 3 setup instead of 2 of 2 and keeping that extra key as the last resort for example if your trezor was destroyed and you couldn't have access to your backup anymore that third key cold come in handy.
I get what you meant but I wonder do anyone need a hardware wallet at all if they can use a multiSig wallet? This is what I do for my log term hold:
I have a 2 / 2 multiSig wallet. Both keys are in two different device. Also I have printed version of the information and they were given to two different person who do not know each other and live in different city of the same country (for the time being).
I feel pretty secure by doing this. I do not think a hardware wallet is necessary at all for me. In fact I have a ledger nano S which I only use for Altcoins.
i myself have a simple legacy setup (address with 1 signature!) as my paper wallet aka cold storage but i have seen these different multi signature setups becoming popular lately. i don't know why but people seem to feel safer if their coins are protected by more than 1 key!