1970 Dodge Dart rear quarter patch panel?

Trying to figure out my summer car projects. As I stare at my driver's side quarter panel, one job is quite apparent. Rust has only attacked the very bottom of the panel behind the rear tire so a complete quarter panel is not needed. I haven't had any luck finding a parts supplier that has rear quarter patch panels for a 1970 Dodge Dart Swinger. Does anybody have any ideas as to where I can look?

Thank you.