[Shagetz unt a maidel?]
Sent to me by an Orthodox (Sephardic) rabbi in Israel:
It could happen!
It is interesting to note the following in the family tree of Kate Middleton, wife of Prince William:
Kate's mother is Carol Middleton, daughter of Ronald Goldsmith and Dorothy Harrison (both Jews)
The parents of Dorothy Harrison are Robert Harrison and Elizabeth Temple (both Jews), the latter a descendant of the Myers family (traditional English Jews in the 19th century)
Bottom line: Princess Kate is a Jew on her matrilineal side, and as a consequence, the future king of England will be a Jew according to Jewish Law and tradition.