Ok so feel free to ignore my ideas they are possibly slightly random but your dress is very simple and elegant and when I saw it I thought a posy of ananomies in a couple of strong colors would work really well.
( I am not a florist so have no idea if they are suitable byut im currewntly toying with this idea for my BMs as they are in 50s stylee dresses)


try these links as well (top one has some lovely images)
http://greenweddingshoes.blogspot.com/2009/05/addicted-to-anemones.html
http://www.ayleebits.com/2009/04/13/wedding-blooms-anemones/