I don't think that we have anything to worry about with the 3D idea being tossed around. Here's the link for Wyck Godfrey's interview where it's mentioned.http://www.fearnet.com/blogs/eclipse/b1 ... dfrey.html
From what I have read, they would use the 3D to differentiate between Bella's vision for pre and post trasformation. Some were posting earlier wondering how they were going to show Bella's difference in vision and 3D may be the only way that they can somewhat pull that off. He states that if it can be done and stay true to the material they will. So they are not even thinking of having the birthing scene in 3D. He also answers alot of our other concerns about that scene as well...like how they are probably going to shoot it. Since we read this from Jacob's perspective, it was a lot more graphic than what Bella would have been able to tell us. If they take it from her perspective, there will be the majority of the happenings, but it will not be quite so stomach turning.
I loved his comment about having his wife, who's an OB-GYN, brought to the set to make sure that Edward makes the proper incision with his teeth for the oral Cesarean.
Over all, it was an enlightening interview as far as some of the concerns that have been voiced. Still hoping Stephenie can fix or at least tone down some of the major mistakes that have been made...