Kewl! have you got a fancy dress hire/party shop nearby or friends in an am dram group? always a good start. Personally I always go out dressed as the King. Can't go wrong with Rhinestones and a burger man. I'm gonna have me a burger and pretty little thing backstage now man, onh-honh. Thang yaw very much.
you could make the dress from that net/mesh like material you hang in the window to allow light in, but prevent people looking in. Should be able to get that in "Shaws"