Overlord, would multibases suit the rules for natives? I'm thinking of 3 models on a 60mm round base combined with single based figures. It would make handling such big units much easier.
Although the rules state individual bases, you could use multibases. It would be better suited to native type armies as they tend to suffer larger numbers of casualties (at least mine do!) to fire combat. It would limit you on movement, closing up/spreading out etc
For melee you match up figures to determine how many opponents any individual is fighting. Not impossible with multibases, but less easy.
The new "Death in the Dark Continent" rules by Chris Peers use multiple figure bases, but I havent seen the rules yet. Others might be better able to comment.