Who needs Osprey Books? The New York Public Library has a gorgeous set of color plates of the uniforms of the Ancient Roman Army.
For Warhammer Ancient Battles, here is a paper model of a Roman testudo in 25mm/28mm scale.
From the Red Rampant site comes an article on Roman Vexilla (flags, or standards). Useful information for anyone building a Warhammer ancients army of Romans.