After some research i uncovered an article describing the differences between the orginal concept for the movie and the film version. I must say the differences are dramatic. In the P880 version there is alot more on earth. In fact a good ten to twenty minutes would be on the Mechanical gray earth with no green.
Then the differences go in quite some odd twists that really develop the story. My favorite of which is a new character named Hegner. Hegner's story really goes into depth about what happens when an avatar dies. In the concept version ((elluded to in the movie)) Hegner commits avatar suicide permanently disabling one of the links in the lab. I found in the movie there is a link that is shut down and has the appearence of being dusty. Hegner did this because his Na'vi love was killed by the military.
Im not going to document every change because that would take alot of time and space i just merely want to get the knowledge out about the concept version. The link to the article is at the bottom. Check it out and post your thoughs below.
The almost Avatar (P880)