Tex Johnson, in a demonstration flight for Boeing, flew a barrel roll. in a 707. It's probably mentioned in his autobiography "Tex Johnston: Jet Test Pilot". There are a couple of youtube video's of it.
I was watching them yesterday; around the same time a European airline training captain was allegedly regularly doing the same on training flights.
As the Boeing boss said to Tex “you know it’s safe, I know it’s safe but don’t do it again”.