I just saw this at Talking Points Memo:
1958 TV Show Had Conman ‘Trump’ Selling Mystical ‘Wall’ To Hysterical Townspeople
Fact-checker Snopes has apparently verified that it is from an actual 50's TV series called "Trackdown."
From the episode (via TPM):
a judge warns the ranger: “I live here, I know these people pretty well, and right now there’s nothing in the world that can change their minds [about Trump] — and anybody who tries to could end up getting hurt. They’re not going to listen.”
“Well, what if he starts a panic?” Gilman responds. “It could happen."
“Well sure, but you might as well try to spit out a forest fire,” the judge says, adding: “It’s funny how a big lie can make us all kids again.”
“I am the only one! Just me! I can build a wall around your homes that nothing will penetrate,” Trump says.
“What do we do?” a someone asks. “How do we save ourselves?”
“You ask: How do you build that wall?” Trump responds. “You ask, and I’m here to tell you.”