For U=R lovers

[Skyblade]

The S=G thing is actually a fairly well known theory, as it is part of the infamous R=U theory.

I will admit that the actually S=G theory has a bit more credibility than the R=U theory in my opinion, so I do slightly believe in it as a possibility, but in order to fully believe it I need to believe the R=U theory, which I don't believe at all.

Perhaps I'm just talking out of my ass here (but that's what these threads are all about anyway!), but doesn't scanning Griever reveal that he was created from Squall's own mind by Ultimecia?

Yes it does.

So really, there isn't so much an S=G theory, as there is a direct line from the game stating it to be fact?

Saying Griever was created from Squall's mind does not mean that Squall is Griever. In fact, it pretty much blows that theory away. An idea and the individual who has the idea are too very different things.
Griever was a personification of an aspect of Squall's psyche. A collection of thoughts and images given form, nothing more.