Complex sentence: There have been several other overseas factories that produced Great Wall models from knock-down kits, located in Bulgaria, Ecuador, Egypt, Ethiopia, Indonesia, Iran, Nigeria, Russia, Senegal, Ukraine, and Vietnam.
Split into simpler sentences: There have been at least eight overseas knock-down factories that produce Great Wall models from knock-down kits. Factories exist in Bulgaria, Egypt, Ethiopia, Indonesia, Iran, Nigeria, Russia, Senegal, Ukraine, and Vietnam.