I'm pretty certain the climate of Southern Arabia doesn't really encourage much too heavy armour. Nevermind in layers. And AFAIK bronze heats up in direct sunlight quite as cheerfully as iron.
Anyway, I know of one Seleucid Legionary design which has a neat big hexagonal shield, greaves, a kopis sword, a crested bronze helmet and several different texture versions for body armour - mail, silvered scales and bronze scales. Some javelins too, which I think would fit neatly in with the way the King's Elites use them even if you can't actually make the officer itself to.

I can try digging up the link.