SF Bay Area hounds with South Bay inclinations are fond of a restaurant called Chef Ding's, in San Mateo. The Chinese name is Louwailou (well, they do have xihu tang on the menu).
I'm told that Chef Ding also has a restaurant in Shanghai now. According to a phone call to Chef Ding's, it's called "xin loushanglou" and is at 428 Tianmu Xhong Lu, third floor. I think that's the "Triumphal Arch" building, right by Sky City. It might be fun to check out and see what the Shanghai branch of an American Shanghainese restaurant has to offer and how well it's doing.