I have ICO, and sadly, I could never get really into it. After I finished SotC, I pretty much had a hard time getting into anything else, cause I just kept wishing I was still fighting colossi. ;-) Elder Scrolls: Oblivion eventually managed to suck me in again... I'll probably give ICO another try sometime. SotC was pretty much an impossible act to follow for any game.
I would probably kill a person for a SotC sequel on PS3. ;-)
Well, not that it's guaranteed, but Fumito Ueda (the director of both ICO and Shadow of the Colossus) is currently working on two games for the PS3. At least that was the rumor last I heard out of Famitsu. Considering that SotC was a spiritual prequel to ICO, it's possible that the new games will tie into that universe. At least, I hope so, because there's so much space between the two that I can only imagine how he'll flesh things out. If you haven't played through/finished ICO I'd highly recommend you do, just for the full experience on how it and SotC are connected.
Of course, he might consider that universe "done" on the PS2 and be gearing up to create a new setting for this PS3 games. One thing that's for certain is that unless he's been hit on the head in the last few years, his "design by subtraction" aesthetic ought to be intact.