You can buy an armadillo in the south and central America.
I work in a leprosy clinic in ecuador in the summers, and the disease is 100 percent treatable when detected early on.
I would not buy an armadillo if it were the last possibility I had for owning a pet. A very large number of armadillos are carriers of leprosy, for which there is NO cure. Leprosy disfigures and eventually kills you. It is a nasty disease to contract. About 95% of people are naturally immune to leprosy, but since you don't know who is who on that, I wouldn't take any chances with coming in close contact with an armadillo.