How about a set of native African infantries to go with the Colonial range. The Zulu weren't the only awesome fighting force to confront the Europeans. I would like a set, perfect for the Stretlets 40+ poses style, of assorted native tribes: the Azande, the Nandi, the Masai, some Askaris and Ruga Ruga. Maybe even some Maori for the Polynesian Islands Colonial campaign. It is the perfect set to make because
a) each soldier, given the lack of clothing in most of these armies (the Masai called the British 'those who trap their farts') would be the perfect armature for conversions to other popular subjects such as ancient Germans and Vikings or Saxon beserkers or Zulus or Greek hoplites, etc.
b) the styles of dress are so diverse I imagine they would be incredibly fun to sculpt. Witch doctor masks and Masai headdresses, what could be better?
c) the poses would be exceedingly diverse.
As source material I recommend Osprey's Warrior Peoples of Eastern Africa and Foundry's 19th Century Warriors of East Africa.
There's always Sir Garnet Wolsey's opponents: the Ashanti.
From primary source accounts, the jungle was so thick that the British rarely or never saw their opponents & just blazed away when fired upon, so an Ashanti army might be furnished from an empty box.
You'd just need a skull throne for the British to capture at Campaign's end.