I know there are several books out there by cavers that would make excellent movies, one of my favorites is Yochib: The River Cave http://www.amazon.com/Yochib-River-William-C-Steele/dp/093974810X/ This was written by our very own Bill Steele and is a very good read, I couldn't put it down.
This book can also be found on cavebooks.com, but I couldn't find a good link to just that book on there. Anyone else have book suggestions, preferably those written by cavers? Charles