I have found much success with Kleinfelds new bridal party attire. Super cute, adorable and many options for different sizing. They go up to size 24! They even have launched a try at home program, about 2 weeks ago. Pay $15 for each piece, may not be the exact size or color but close enough to give you a good idea!
Another vote for Azazie! Daughter's BMs ranged from size 6 to 18, barely 5' to 6', and their dresses from Azazie were awesome. Four of the five ordered custom sizes (no additional cost, and includes a credit for additional alterations), and all of them looked beautiful on the day of the wedding. Daughter looked at DB first, but there was NO comparison on price, quality or customer service with Azazie. (If the online thing bothers you, do the try-on option for $10 -- it will convince you.)