Alright, this will be an arduously long post where I first try to clear some of the confusion regarding certain plot elements and then I will continue to post my take on what's the movie is about. As for my research, if you can call it that, I've viewed all the footage of the trailer, comic-con footage which people seem to have forgotten about, sets pictures, articles and sky.com leaks/news.
'The movie will not involve any xenos or things resembling them.' - Wrong
Answer and source: “Despite that press release that seemed to indicate there were no aliens in the movie, the familiar HR Giger-style aliens do appear. Big ones apparently.”
“An exclusive source has told us that not only are HR Giger’s classic aliens in it, but that they’re integral to the plot." - source to sky.com 04022011
'Then you mature and ask what are the tasks at hand, and he said: 'You've got a tall order here because you have to do something that's better than Giger' Now you're scaring me, because I just don't know if that can be done.' - Neville Page, Creature designer on Prometheus.
'The movie will be at LV-426'
Answer and source: Unclear at this point. No definite answer. But considering the look of that planet to the planet we see in the trailer, the answer is probably not. Also, Lindelof said in an interview that the ending will NOT be the derelict ship at LV-426.
'The ship in the trailer, is that the derelict ship or not? How is it piloted controlled and by whom?'
Answer and source: Lindelof denying that the end will be the derelict ship at LV-426. So the answer is that it is not the derelict ship.
'people are going to be in for a shock when they sit down to watch Prometheus and there’s an enormous semi-human head piloting a spaceship.' - source to sky.com. - The big head seen in footage then, geez..
'Is the space jockey the man in the corner in one of the trailer pics?' - Probably not
Answer and source: An eight foot animatronic will be the space jockey - source to sky.com
If it was a human, then they wouldn't need animatronic.
According to rape scenes, mutation and so on - no sources, so why assume it? Just assumptions. The comic-con footage showed elizabeth shaw being examinated around her belly though. Here's an excerpt from a guy who has viewed the comic-con footage:
There is Charlize Theron on a table with bandages wrapped around her breasts, as though she's waking from hypersleep.
And then the footage gets faster and more furious, with a guy in a visor looking down at something, a woman in a suit walking into a red entryway, and a globe, and then Scott says, "The cast find an establishment which is not what they expected it to be, it's a civilization but what we find in it is very uncivilized behavior." And then there is insane carnage and people with goop inside their space helmets and someone shooting a flamethrower, and mayhem breaking loose in confined spaces. Meanwhile, Scott's voiceover is saying that there will be biomechanoids and the film will "break new ground." We see a giant pale planet with rings around it."
Biomechanoids confirmed, bandages.. the scenes we've seen from the trailer? Probably not mutation in the scene with holloway and the helmet, as they walk around with goop inside their helmets.
My take on the plot
They arrive at the planet. They drive out the temple, find the urns. David takes one of them back to the spaceship for investigation. Meanwhile, the rest of the team continue to investigate the site, when the shit goes down with the goo in the helmets. The urn, which is now in the spaceship, now infect certain team members which causes them to mutate/change. The giant head, which is the pilot/remnant of the space jockeys, pilots the jockey ship after it discovers that one of the urns are stolen, which is of course forbidden (stealing fire from the gods - prometheus).
The rest of the crew, who has survived the goo in helmet thingie, run in panic away from the temple, and drives back to their ship. Notice that its just one car back to the ship in trailer, while there are like 4 viechles going there. Shaw stands at the door to the viechle bay, and see everything just explode in a dust storm as the ship emerges / take off. They haven't noticed yet that jockey ship has emerged, just the storm/bad weather. Meanwhile, one of the crew members inside the ship have gotten infected due to davids urn, and jumps towards the surviving crew members from the temple as in the scene. He escapes and jumps into the jockey ship where we see his final form in one scene. Now the surving crew members are being analyzed and shaw is identified as having something in her abodomen, shit goes down in the ship for now.
Later more chaos begins, in which we see vickers jumping into an escape pod, the derelict ship crashing down probably due to prometheus crashing into it to destroy it.
Alot of gaps and holes to fills, but thats my take. Where xenos and the actual jockeys fit in, I don't know.