I see something like this, based on what was said in Breaking Dawn... about the theme of the wedding being around Edward.
He was born in 1901, and immortalized in 1918..... http://dept.kent.edu/museum/costume/bon ... -1919.html
First series of pictures on Top.... Effie Crafts's dress.
Think Titanic period....
There is a part in the book that talks about a series of buttons on the back of the dress.....and there is no talk of cleavage, or bare shoulders... but there was a train she was afraid of tripping on going down the stairs.
Although that model doesn't look like it has buttons, the style would seem to fit though.
Check the buttons on this beauty !!!!..... http://www.bestbridalprices.com/allure- ... Path=1_106
Even something like this.... even if it's not at all from the right era :http://www.bestbridalprices.com/amelie- ... cPath=1_29http://www.bestbridalprices.com/bonny-w ... cPath=1_32
But THIS one hits the mark for me. This is how I imagine Bella's dress.http://www.bestbridalprices.com/casabla ... Path=1_110