Several European retailers, such as Amazon and Shopto, are offering an exclusive steelbook with the Metal Gear Solid V: The Phantom Pain Day One Edition. The case features a Shinkawa artwork of Big Boss on the front and a Diamond Dogs logo on the back.
It also has another Shinkawa artwork on the inside.
Judging from the product page you get both the normal case for the Day One Edition and the (empty) steelbook.
Source: Amazon.de, Amazon.fr via Reddit, metalgearsolid.be, Shopto.net via MGSFansUK