Probably not appropriate on Dwilight. Italian medieval city state republics would fit with the current Europe focused SMA, though given the influence of Greek thinking on western Europe, you could probably make a case for it. I presume you refer to the Athens style republic, because like so many things no two Greek City states agreed on the principles of a republic, not even all city states WHERE republics.
Athens was a republic in name only for a lot of it's history if I recall, various oligarchies or tyrants held the majority of power. Just an influence mind you, not an overt Roman republic
