I used to have one years ago, but sadly I don't know what happened to it. This isn't mine. I stumbled upon it while looking up XCM stuff. It has the Parallel and USB access ports for the Viper GC and Viper GC extreme programmers.
Full Clear GameCube XCM shell (not my pictures) https://imgur.com/gallery/4yPAatT
Full Clear GameCube XCM shell (not my pictures) https://imgur.com/gallery/4yPAatT