Yet another case of "Phantom Grappling Hook Syndrome". Check out this link for an article on the nature of memory.

http://www.cracked.com/article_18704_5-mind-blowing-ways-your-memory-plays-tricks-you.html

It might surprise people just how much Star Wars stuff is preserved from the early 80's and some record of a George Lucas interview (video or magazine article) would have surfaced by now.

As for visual evidence of the missing scene, bootleg videos taken from 1977 prints are available on the net and believe it or not, actual film prints (both 35mm and 70mm) exist in the hands of private collectors. If the scene existed, news of it would have leaked onto the internet following one of the many "private screenings" we often hear about.

I'll throw down a challenge open to anyone all over the world.

You find and post video evidence of this scene , then I will give you 100 English Pounds for finding it.

However, my guess is it's as rare as rocking horse poo !!!