Your hypothetical is a silly, inane, stupid and impossible hypothetical which is designed merely to distract from the subject of this thread, which is whether Ted Cruz is eligible and not whether a hypothetical Prince of Wales would be eligible to be King.
Now get lost troll.
No. There is absolutely no reason that the scenario is "impossible", just incredibly unlikely. It's unreasonable, I think, however, to suggest that the language of the Constitution doesn't somehow cover the case in question.
Could the heir to the British throne, if he had an American citizen father, be eligible to become President?
Despite how unlikely or inane you might think the question, does it not have an answer? Are you hesitant because you recognize that a "yes" answer is ridiculous on its face and would suggest that our Founders didn't fear another monarchy; and you recognize that a "no" answer would require an explanation as to how and when the rules changed such that some other foreign citizen might be eligible.