It's decided

After checking with my imagineering consultant, Kim, I've decided to try to put together a costume for Captain Graff (better known to most of you as Colonel Graff) for the Halloween Party I'm attending. Of course, I most certainly won't win the prize money if Conor goes as Blaise Pascal, but it's not about the money. I'm guessing I can use my tux pants for the lower half of the costume, but does anyone have any recommendations for ways to dress up a sport jacket or a place to cheaply buy something that looks like a military uniform from the 2200s?