Do you actually use this definition for moral purposes‽ If so, it would seem that psyhcotropics drugs / brainwashing would be a much easier method of "identity preservation" than all this messy business of freezing people or storing full brain states or whatever. Indeed, you could live indefinitely with nothing but a colony ship of gullible uninquisitive people who have been taught really weird philosophy, and some self-inflicted brain damage. Am I misunderstanding you?

Edit: Or more concretely, just start a brainwash-y cult with some "We are all one consciousness" woowoo and then immerse yourself in it / smash yourself in the head with a brick until you believe your own doctrine. Heck, I'd be surprised if this hasn't been done already. Those New Age gurus really are extending their lifespans!