Not sure if it's ok to post links here or not, but I hope it is. What about something like this?
http://www1.macys.com/shop/product/alex-evenings-plus-size-beaded-tiered-dress-and-jacket?ID=662549&CategoryID=37038&LinkType=#fn=DRESS_OCCASION%3DEvening/Formal%26SPECIAL_OCCASIONS%3DMother of the Bride%26sp%3D1%26spc%3D27%26ruleId%3D%26slotId%3D17
Or this?
http://shop.nordstrom.com/s/adrianna-papell-beaded-illusion-gown-plus-size/3347657?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=Lead&resultback=571&cm_sp=personalizedsort-_-browseresults-_-1_2_D
I love Adrianna Papell dresses. I just feel beautiful when I wear them. The fabric is always very form flattering.
Try a bunch on, you'll know when you find the right one, it will just feel right. Just like I'm sure your daughter felt when she found her wedding dress. Good luck, congratulations and have fun!