Sean Flynn, son of Errol Flynn. Sean disappeared mysteriously in Cambodia in 1970. His remains were apparently found two years ago. Sean did a couple of Italian Swashbucklers in the 1960s.
John Gable, Clark Gable's son. Clark was in MUTINY ON THE BOUNTY (below). John was in the news recently about some mysterious death of a friend.
The Son of Spartacus, Michael Douglas, aka son of Kirk Douglas. Kirk had several kids but Michael was the one that had a successful career in movies, with no PEP film in his resume though.
John Drew Barrymore in ROME AGAINST ROME; John D is the son of stage and MGM legend John Barrymore. Both Father & Son have had extensive careers in the PEPLUM genre.
Last but not least, Patrick Wayne was a PEPLUM star as his father, John Wayne, who appeared in THE CONQUEROR among a few other films. Patrick is still with us.