The volume in question (also called "The Passover Plot") was written by Hugh J. Schonfield in 1965 and proposed that Jesus did not really die, but that he faked his own death in order to perform the miracle of raising himself from the dead. However, in contrast to "The Da Vinci Code", "The Passover Plot" was written in more in the style of non-fiction. There were two parts, the first which commented on Jesus life and ministry as it told the story, and the second which looked at "The growth of the legend".
Yet the film, which starred Zalman King as Yeshua (Jesus) and Donald Pleasence as Pilate, was drama not documentary, which presumably means screenwriters Millard Cohan and Patricia Louisianna Knop had to do a little work than would normally be the case for an adaptation. Despite being nominated for an Oscar for Best Costume Design, it appears the film was not well received. 2005 saw the book's 40th anniversary, and a year later Tom Hanks was donning his swept back mullet, but neither occasion prompted anyone to re-release it in the hope of making a quick buck.
There is, however, a trailer for the film on YouTube that gives a few insights into what the final film was like. Perhaps I'll get to view it someday and report back.