Are there areas in Taipei that could be considered something like “Thailand-town”? Places with Thai shopping, Thai restaurants, etc?
In Taipei City not really, but there are a couple very small Thai areas in New Taipei City and Taoyuan.
New Taipei City (in an industrial area), take the MRT to Yongning and take a taxi to “Tai Guo Dian”:
New Taipei City (Xinzhuang, a few shops/restaurants scattered on Xinfu Rd.):