A bit obscure this. Taking a step back to Rome 1849, what figures could be used for the Republicans? I'm guessing piccioti, some Spanish guerillas, possibly irregulars from the carlist war range and maybe a few garibaldini (but not in red shirts apparently) and a few Sardinian bersiglieri.
On a similar note, I'm thinking communards could be general late 19th civs, with a few semi uniformed Kepi types in there.
Am I totally off course?