This is the info i gathered from it, some of this info is from people I know, but it seems possible.
“there are alot of theories going around the net right now about the X men movie. The general concensus is that none of the main characters actually die. We never see Scott actually obliterated, we just get a weak explanation saying he’s dead. People are saying maybe Jean Grey coccooned his body during the blast, thus saving his life. And since we do never actually see “The Phenoix,” many people are saying she never really did take the form, and maybe the phenoix will arrise from the grave in the next x men series(which fox already said they’re doing). All in all, this just goes to prove that X men 3 was kind of just a waste of time and doesnt really do anything but messes with the whole mythology of characters and pisses off all the fans to the point where we’re making up these vague outlandish statements, just to try and keep the characters around. Hoefully fox learns their lesson and takes their time from the next trilogy.”
ALSO:
" >“Yeah, the studio didn’t even know I did it,” Ratner told Superhero
Hype. “I didn’t even put it on the schedule. I shot in between set-ups,
just went over there and shot it, and then I showed it to the studio and
they went ‘Oh My God, we love that!’ because it keeps Xavier. Look, in
the last one, Jean Grey died and then I saw her on the first day of
shooting X3, so nobody dies in these movies? What the hell are they
talking about?”
“I was aware of three endings for this movie, all under different
circumstances,” confirmed Patrick Stewart when asked about it. "There
was the ending in the script, which we all saw. There was a scene, which
I shot in the hospital bed, in the first days of filming. It never
appeared on paper, there was no call for it, it was never documented,
this scene. It never got shot. In other words, we sneaked it in after
lunch one day and there were not many people on the set. It was a
cut-down crew, and it was all done very hurriedly because they stuck a
beard on me over lunch and we shot it. Then Ian [McKellen] called me a
few weeks ago and said, ‘You won’t believe this but they’re coming to
London and they’re going to shoot the final scene of the movie,’ which
is of course is of interest to me. He said, ‘I’m playing chess’ and of
course I wanted to know, ‘Who with?’ and he said, ‘They won’t tell me’
but of course there’s no one there at all. Last night, when I sat down
to watch the movie for the first time I had no idea how this was going
to be resolved. We were all on our feet leaving during the credits when
someone from Fox said, ‘You should sit down. It’s not over yet.’ I
couldn’t imagine what that meant and then sure enough, there was this
little hospital scene, which is hinted at in the video I play in the
class, about a man who had terminal cancer and you can transfer
somebody’s consciousness into him. Something I missed last night is that
Olivia Williams, who plays Moira [McTaggert], is in the memorial scene.
This seems to support that the Prof is not really dead. What do you think of this possibility?