> Somehow I feel they're safer in muscle memory than in 'normal' memory.

From my understanding, muscle memory is formed when a task is repeated frequently. It's basically like your "normal" memory caching these motions. So, in theory, you should at least _know_ your memory cached passwords.

> And there is the problem of getting locked out after too many invalid logins. I have enough passwords and variations that 3 times just aren't always enough attempts.

Ah, I hate it when that happens. Have you tried using a password manager like LastPass or 1password?

edit: https://lastpass.com/