Call David's Bridal and ask about it.
what do you call are person that designs beds
Well you could just search bridal gowns or you could also search wedding dresses. If that doesn't work than just go to a wedding dress shop on line and maybe you could order the dress you want. You should probably just go to David's Bridal gowns. But before you do you should note that if you call of the wedding they won't give you a refund.
A person who designs buildings is an architect
Try "a designer"