HMV has one, even Virgin Megastore has one. (I think even WH Smith have them in the "chart") Incredibles and Finding Nemo are 2 disc sets. Not sure about Monsters Inc (can't tell if it is one or two discs so haven't got it yet).
According to
Amazon (Monsters Inc) it is two discs with shit loads of extras. And the cover art on amazon says Collectors 2 Disc Edition. Don't remember seeing that in HMV or Virgin Megastore. It is the widescreen collectors ed I want (if I get it). Not the standard version (poss full screen).