There's a "farmer's" market near my old house where the various shops are run by either Mexican immigrants, Asian immigrants, or Middle Eastern immigrants.
You can buy just about any chili that I've ever heard of or read about in one of their shops. The common ones, common to America that is, are available fresh, but the other more obscure ones are sold dried.
My favorite shops for chilis are the Mexican ones. There are more types of dried chilis than you can shake a stick at. (Why you would want to shake a stick, or end a sentence with a preposition is beyond me).
I made an excellent chili powder last year using dried serranos, anchos, chipotles, pasilla, and mulato chilis. It was 1000x better than any store bought chili powder.