Just was in Shanghai for 3 weeks. Went to Tianshan as well as Laoximen tea markets (didn't get to any of the others). I found quite a few shops selling both Wuyi yancha and Wuyi area red teas (zhengshan xiaozhong, jinjunmei). So, compared to Jason's last report and some posts on Sanzui, I was pleasantly surprised to find some yancha to buy, and I think I managed to get a few decent ones.
Lots of shops selling pu'er (younger in most cases, though some shops had older stuff), but didn't have the time, energy, or money to delve too deep.