I think that this is a perfect chance for a label to pick up this and make a complete score release of Jame Horner's wonderfully composed music for the film. I think that it would be a prime opportunity for something like this to happen. I would buy the complete score on CD in a second, especially if there were even some signed copies involved.
I have never seen the film. Is there really much substantial material to expand? The original MCA album has a quite generous running time (about 67 minutes of the score with the movie running 100 minutes) and IMO already has some fillers on it.