V For Vendetta: Who Was V, Really?

I just finished reading Alan Moore and David Lloyd's graphic novel V For Vendetta, upon which the movie of this past spring was based, and I have a question....

Since this concerns the ending of the book, if you have not read V For Vendetta or seen the film (though, not having seen the film myself, I have no idea how closely it follows the book), you might want to skip this entry and go to the Big Brother update.

Throughout the book, we never see V's true face, and then at the end Evey Hammond assumes the mantle of V following V's death. As I was thinking about the ending this morning, the following thought hit me: Is it possible that V was, in fact, Evey Hammond all along and the conversations between her and V took place entirely within her mind? Therefore, the new "apprentice" that Evey/V takes in at the end of the book would be yet another manifestation of Evey/V's psyche. After all, Finch says that V is not a normal human mentally and actually goes so far as to take LSD in order to think the way that V does. Plus, this is written by Alan Moore, so it makes sense to assume that there's more going on in the story than meets the eye.

If you've read the book, I'd appreciate any thoughts you have on this subject.