Agree that they're most likely custom. They're made of folded sheet metal. I think sites like Ponoko will do custom designs in very small quantities (1?) but it's probably very expensive there.
Some people buy a bending brake and attempt it at home with aluminum sheets, although depending on the folds, fancier shapes can require more specialized machinery. This one looks achievable on a basic brake. Getting it to look professional is the challenge, and you'll probably want to stick with aluminum if you do try that (whereas steel is sometimes used for this enclosure style for a heavier and sturdier case).