... formal clothes for tweens to rent?

A friend suggested I try a Wedding Album shop, like those on Zhongshan N Road, Sec 2 (near Datong) or on Ai Guo by CKS. Does anyone have any advice or recommendations on places that may let us rent for the weekend?

Maybe I could get away with a borrowing a Dracula costume (ok, sans cape) or something like that from a Halloween shop