I'd love to see something similar for encrypting a 12/24 word seed. Even better if the result is just represented as a seed again: to restore, enter the encrypted seed, the password and wait a few seconds (yes, seconds!) to decrypt it. I'd feel much safer than just storing the unencrypted seed words in plain text.
I'm still struggling to understand why you need something other than the currently available plain text encryption options. This really does seem like reinventing the wheel to me... Is it because you want wallets to provide built in methods to encode/decode the mnemonic string?
Noting that if you end up with "random" text, it sort of defeats one of the core purposes of the mnemonic in the first place... ie. reduction of transcription errors.Turning the result into another mnemonic string sounds like it should be possible... but then, why not just use the original seed and a strong BIP39 passphrase? Surely this ends up effectively resulting in the same thing... a mnemonic string + passphrase?
It seems like creating a .zip file with a password and then putting that into a .rar archive with another password... or am I missing something?