Wanna bet Parbot owns the copyright and not Lucasfilm and they would have to pay him a pretty penny to sell the rights.
Something tells me he would not want that anyway since he does not want it shown, which is strange.
I mean its referenced in the making of book by Rinzler in like a single paragraph.
Making it available even through folks like the BBC or PBS in the USA would be ideal because of its educational value to film students, or to film history studies.