The only 'ragged' troops I can think of off hand would be some of the confederate types (Might be worth trying redoubt, as they've got a seperatre head system so it might make conversions easier) and maybe try mixing in some Boers, but painted in a semi-uniform way?
If you want to add some renagade colonial units, there are some mahadists in ragged (egyptian?) uniforms in the redoubt range, and I think some from the perries too. There are also the Foundry semi-uniform askari's for a similar sort of thing.