I also think Padmé will not die in Ep3.
Anakin's journey to the dark side (get your ticket here) will be complete by the time she finds she is preagnant. Looking for protection she once again turns to the last Jedis. Together they decide he shouldn't find about it, wich he does but only that she is preagnant not that there's two of them, and they also decide to split them up since together they would be easy to find using the force. So Luke goes to the closest thing he has to family with Obi-wan to keep an eye on him, and Padmé goes with Leia to Alderaan under the wing of Bail Organa. I think it would be a really strong scene in Tattoine with Padmé giving her son to Owen and Obi-wan conforting her saying he´ll always protect him.
Then she goes to Alderaan but she dies some years later probably as the news of her "late" husband's "achievements" arrive and the fall of the Republic is evident...
Anyway it's very sad, very greek tragedy style.
Yes, I forgot that line, but that suports my idea that it is not Padmé's death that will put anakin on the dark side. Obi wan and Yoda hide her before the pregnancy is evident because he already is Darth Vader at the time. And THAT puts a lot of time stretching between Anakin becoming Darth Vader (main plotline of the movie) and the birth and separation of the children and then the death of Padmé. How long is the film anyway?
But there was one thing I never thought well explained in the first two movies was if Darth Vader is or is not aware of having a child. He doesn't seem too surprised when he finds out. Does he?
Its already been confirmed that EPIII will clock in at around 2 hours, give or take just like all the other SW movies. And although this hasn't been confirmed its my guess that the timeframe within the movie will only be a few days just like all the others. As for Padme's death, I hope she does die onscreen(not trying to sound morbid) but leaving her in limbo would suck.