Milan soldiers under the Visconti wore a combination of red, green, and white. I guess that you could play with it to include mostly green and white...
Naples' soldiers wore mostly red and yellow. Siena militias usually wore grey and white, but you could play with the contrada's colors to create colorful regiments.
Usually, only town militias and provvisionati (permanent soldiers directly serving the state) would wear the town's color. Condottas would bear the banner of the town they were serving but not wear their colors. The knights and household soldiers of the captain would wear his personal colors but the main body of the condotta wouldn't wear heraldic devices.
Hope I helped!!