What I am absolutely sure of is that once the extended editions of all three movies are out, complete with any bits of deleted scenes that might turn up in the extras, someone will cut it into the best guess of what it would have looked like. And someone will cut it into something that better approximates the book. And, undoubtedly, various other versions will turn up.
There's a massive Fan Edit scene out there, with lots of available versions of a vast variety of movies. It's not something that I spend a lot of time looking into, but I'm really glad they exist.
Original post on Dreamwidth - there are comments there.