All that space on the disc isn't to store multiple versions, it's to store the high definition picture and uncompressed (or compressed at a very high bitrate) sound. The Blade Runner Blu-ray and HD-DVD releases are five discs just like the five disc dvd set with the Deckard briefcase. I assume the Close Encounters Blu-ray will also be the same number of discs as its dvd counterpart, which at the moment appears to be only one disc.

What's selling the new high def formats isn't the amount of extras or even the number of versions of the movie, it's the 24 frame per second playback (I would think people in PAL land must be eating this up), the 1080p picture and the 7.1 audio.