I have a problem swallowing the Prince and the Pauper thought experiment. Though the handout on "Personal Identity" says, "whether it has ever or could actually happen is irrelevant." I think it is very relevant. Our ability to abandon what our senses, our science, our logic, and our feelings tell us to engage in fantasy has little bearing on our ability to understand reality.
As far as we know, it is impossible for such a "body switch" to take place. The ability to switch is neither a trait of the body nor of the mind. Because the mind and the body are inherently "unswitchable," it seems of little use to speculate what the ontological ramifications of a "switchable" mind and body would be. Certainly, if we found a case in which such a body switch had occurred, Locke's point becomes a valid argument and an ontological question in its own right.
In trying to understand the way the mind and the body are related to personality, why would we hypothesize that the relationship between the mind and the body is completely different than we intuitively and empericaly understand it to be?
This reminds me of an article on abortion I read in my ethics class that likened abortion to the killing of imaginary space aliens.