I've read about the Mfecane which I believe means "the crushing" (called "Difaqane" in Sotho). Maybe you know about this already. Besides Mzilikazi who led the Khumalo out of Zululand and created the Ndebele nation, there was also Zwangendaba and Shoshangane. They were commanders in the army of Chief Zwide of the Ndwandwe people, who were enemies of Tshaka (or Shaka as we tend to spell his name in Britain). When Tshaka defeated Zwide, Zwangendaba took some followers and migrated north, conquering and incorporating other peoples along the way. His people became known as the Ngoni, and they broke up into several groups who settled in Malawi, Zambia, and even as far north as the shores of Lake Victoria in Tanzania. Only a minority of Ngoni speak the Ngoni language today (which like Ndebele is very similar to Zulu). Most speak the languages of the peoples whom they settled among.
I'm not quite so sure what happened with Shoshangane. I think he took followers and conquered some of the Tsonga people of neighbouring Mozambique, where the descendants of his followers are known as the Shangane (or Shangaan) people.
By the way, are you a Rastafarian (I'm not). What do you think about traditional African religions such as the religion of Mwari?