I have no idea, but I ordered it. I think it comes with the soundtrack, and an art book. Which is really why I'm buying it; I can't stand MGS games, but the artistic value is really through the roof.
edit:
Featuring collectible packaging with exclusive artwork by famed Kojima Productions illustrator Yoji Shinkawa, the Metal Gear Solid 4: Guns of the Patriots Limited Edition will contain everything that is included with the Standard Edition as well as an additional Blu-ray disc featuring two “making of” documentaries. The documentaries will include extensive interviews with Metal Gear Solid creator Hideo Kojima and the Metal Gear Solid 4: Guns of the Patriots Soundtrack CD. The Limited Edition will be available exclusively at GameStop.
No art book.
*canceled*