Belmont Army Surplus has been happily catering to the needs of punks, hipsters, and even regular ol' folks who just want a cheap deal on vaguely military looking clothing for decades.
A friend bought a surplus greatcoat here before - I have no idea which war or era it was designed for, but it seemed to keep him reasonably warm even in Chicago winters, which is always good.
Worth a stop by if you're in the Belmont shopping stretch. As an aside, Belmont, Clark, and Halsted seem to have the largest concentration of independent retailers in Chicago. Good to visit especially since the rest of the city has been overtaken by big box shops.