I don't know how far down people read the board, and I thought it deserved its own subject heading. I went to Thai Binh at lunch yesterday for a banh mi and they were taking apart their counter. They said they were looking for another location nearby, and that they would post a sign in the window of Thai Binh when they found one.
Meanwhile, I will say that the barbecued beef banh mi I got from Mix Bakery was fabulous as usual. I actually prefer it slightly to the ones from Thai Binh -- I like the bread better and it's nice watching the lady carve the vegetables individually, and snip the cilantro stems into bite-size pieces. As long as you don't get the occasional sandwich with over-aggressive mayo-slathering, I'd say it's just as good as the Thai Binh version, though slightly different. Also, they'll make them with tofu, so vegetarians can share the joy.
For those who still crave the Thai Binh version, you can visit Banh Mi Ba Le in Dorchester, which is the home base of the Thai Binh counter.