Entertaining thread...though it's making me procrastinate a lot.
His Royal Highness Crown Prince Emanuele Filiberto di Savoia
Felipe de Borbón y Grecia, Crown Prince of Spain
Carl Philip Edmund Bertil, Prince of Sweden
Louis Alphonse de Bourbon, Duke of Anjou
HRH Prince Alexander of Yugoslavia
Amedeo Marie Joseph Carl Pierre Philippe Paola Marcus d'Aviano, Prince of Belgium
Philippos, Prince of Greece and Denmark (I couldn't find a more recent pic...he is about 19 now.)