I did manage to find a couple of fabric stores in Boston. I wouldn't call either a quilt store.
The first one that I stopped in is called Winmill fabrics. While it is located in the China Town district, it is run by a couple of older Bostonian ladies. A large selection of all kinds of fabrics, including quilting cottons, but nothing particularly new or current. In fact, I saw calicoes from when my mom started quilting probably more than 20 years ago. On the plus side, it is all quite inexpensive, with the cottons averaging just $4.00 a yard. I did pick up just a bit. Blue and white for a future project in my head. Thomas for a boy who may or may not get a quilt before he grows out of Thomas and a great tie-dye with lots of color variation.