Deleted scene filmed in 1976 involving Vader and/or the Emperor regarding the fact that Anakin's son Luke is still alive??? Not likely. I don't know where McCallum gets his info but why would this alleged "deleted scene" have not surfaced SOMEWHERE in some form over the past thirty years? Particularly in either the novels, radio dramas or annotated screenplays. A FILMED scene!

Don't you think that after the big revelation in ESB (or especially after it's confirmation by Yoda in ROTJ) they would've rushed into the archives, dusted off the film cans and spliced that puppy right into a re-release of ANH to build support for the plot twist?

Nah. I don't buy it. Doesn't exist. Never existed. DICK McCallum (sic) doesn't know what the hell he's talking about.