I've asked for this title for years (I think Columbia or Paramount owns it). Considering how many people involved with The Third Man were also involved wih OMIH, I'm surprised it has never been considered, especially after the horrible "remake" The Tailor From Panama.
About once a year I dig out my worn VHS copy that I made off of PBS in 1982. The picture is very fuzzy, but the movie is still great!
Our Man In Havana was a Columbia release in the United States so I assume they own the rights.
As for The Tailor Of Panama, Larry, since it's based on the John Le Carre (The Spy Who Came In From The Cold) novel of the same name, it's unfair to call it a remake of Our Man In Havana. More accurately, perhaps you should refer to Le Carre's novel as a horrible "remake" of Grahame Greene's novel, Our Man In Havana.
I quite liked Tailor myself but would eagerly welcome a DVD of Our Man.