Sometimes a strange car will gain a sort of "cult" following, and that's when you sometimes end up with a situation like you describe, where parts are made by many different 3rd parties. I have an old Japanese 4x4 that was so awesome that Mopar had to team up with consumer reports and the government to kill it. It's 30+ years old and I can get parts for it as easily as I can an F150.
Notable past and current examples of this include: