Blah, stupid idea.
What made ICO ICO, was the characters and story, not the engine.
Maybe some game that is set on the same ICO universe (with horny boys etc...) but as far as I see it, the story of ICO ended, and should rest in peace.
No ICO prequels or sequels, but a spinoff would be acceptable.
Edit: Oh, I see that was maybe just what you meant l-b, sorry.