Well, I think that the source is this: https://twitter.com/riesgoyfortuna (sorry if yet posted).
These guy as know as "blue_eyes" leaked many years ago Shadow of the Colossus in MeriStation, a spanish videogame forum. So, I think this is not fake.
Well... damn, you might be right. This could possibly be the guy that leaked SoTC.
http://es.wikipedia.org/wiki/MeriStation
Google translate says: "March 25, 2003 a user of MeriStation (blue_eyes) leaked in several forums video games, including the magazine, the first catch of the sequel of ICO"