shield designs

[Shield And Spear Art]

Go to total war center (twcenter.net)and check out some of the mods that people do for the Rome: total war games.  They are usually very well researched and I am sure you could ask them where they found their sources.  Also, the Osprey books have a lot of good illustrations that might help. They have books on most of those cultures I believe.  Just do an amazon search.