This must be ancient, but I never heard any speculation about it so I had to ask..

 
I just watched the original E3 reveal of The Last Guardian, the trailer thats 4min and 37 seconds long, and noticed that when the title fades in, it says ICO first. The L, G and D light up only partially to look like the letters I, C and O at 2:27 in the trailer. It happens really fast. 
 
Once again, I know this is from the age of the dinosaurs but I never heard any talk about it. Also, why reference ICO when SOTC is more current? Man, I REALLY want TLG right now.
    

Once again, OLD, I know. Forgive me.

Dang, nice catch. My not-so-exciting guess would be that it's just in reference to the Team ICO name as opposed to the game, but who knows, maybe it is hinting at a connection between the two games. I wouldn't be surprised, but Ueda-san is on record saying they haven't made the decision to tie them together yet, something about that being something they'd finalize near the end of development which is probably about a year away still.

"Dang, nice catch. My not-so-exciting guess would be that it's just in reference to the Team ICO name as opposed to the game, but who knows, maybe it is hinting at a connection between the two games. I wouldn't be surprised, but Ueda-san is on record saying they haven't made the decision to tie them together yet, something about that being something they'd finalize near the end of development which is probably about a year away still. "