If there are female shoppers, i recommend Hong Kong Industrial Centre, its sort of a wholesale centre for women's stuff - shops in mongkok, etc get their stuff from here. Some shops do not sell to consumers, but most of them do and at great wholesale prices. There're also adidas and umbro outlet stores in the building (sadly, the only shoppable places for males).
Directions: Lai Chi Kok Station, exit C if i remember correctly. u should see a shop selling freshly baked bread when u exit. Shops there are closed on sundays.