I find this to be VERY hard to believe. It might be plausible for a smaller film but this definitely does not apply to a modern big budget flick like this one. It's well known that this movie underperformed in the theaters which is precisely why this will be an intentional "double-dip" by the studio. Get as many sales from the single disc then sell the two-discer (possibly a "director's cut") at a later date to screw over the hardcore fans.
Perhaps I wasn't too clear on what I said before. What I meant to say is that, based on my internet research on the different DVD versions for "The Island" (R1, R2, R3, etc.), all of them do not have extensive features in them. So if Warner were to release a special edition DVD for this to include all the features from all the different regions, it seems there isn't enough to fill two discs. This doesn't necessarily mean that they lack the material. Warner must have opted not to release them yet. Maybe in the future, yes, in DVD or in another format. But as I said, based on available material from all versions, a two-disc DVD is unlikely.
By the way, I watched this release yesterday. The PQ & AQ are indeed good. Especially the AQ. And that's just in DD. Imagine if they pumped it up to DTS pa!