If you're on Facebook
Join the Warner Archives group as a fan and request Treasure Island be made available through the Archives program.
Warner Archives is the relatively new deal at Warner Brothers where you can order a movie from their list and they will press a DVD and send it to you. There's no extras and the chapter stops are every ten minutes rather than at logical spots--BUT YOU GET THE MOVIE.
So far, Treasure Island isn't included on the Archives list. But Warners is at least claiming that they'll pay attention to suggestions made on Facebook, so it's probably worth a try.
http://comicsradio.blogspot.com
http://radioserials.blogspot.com