You can visit the South Bund Fabric Market/南外滩轻纺面料市场 for tailors 399 Lujiabang Lu near Zhongshan Nan Lu/陆家浜路399号
近中山南路 this is probably the best place to go to get your money's worth. Go during the day durin the week to avoid big crowds. 9am-6:30pm. Another option is Couturier http://www.couturiershanghai.com/ it's a small boutique run by a Japanese lady. I've heard nice things, you can have items made here and avoid the market crush. Another place to check out is Dutch Items Shanghai, it has ready to wear clothing from a Dutch designer. They have 2 boutiques downtown in Ferguso Lane, Block K, Room 111, 376 Wukang Lu near Hunan Lu Hours: 10am-6pm M-F & Sun; 10am-7pm Sat Tel: 6126-7661, for other options check out the listings on www.smartshanghai.com, www.urbanatomy.com or www.cityweekend.com.cn/shanghai