Well, though that isn't the tradidiotnal armor of the roman warrior, it still looks kickin'. And he can just be a general or something. Anway, I would say give him a tower shield (easy to find or model edit) with a Legion number on it, then give him a Gladius (just use a short sword and edit the skin, it'll look great.
nice breastplate...lookin very good for a WIP.
also if you want to make a nice gladius for him, make the swordguard rounded and skin the bottom as if it was wood. (if you have a model editor at hand.)