I started on this a couple of weeks ago, but since I've seen a few people on the Steam Workshop requesting a proper Rise of an Empire Athenian unit reskin I thought I'd post my progress.
I made all the new uniform pieces from scratch, which include bracers, boots, belt/skirt, 2 helmet types w/5 crests and 3 faceplate variations, 3 variations of torso straps and 2 cloaks (cloaks look like balls though so I'll probably just end up using CA's cloaks...I suck at sculpting fabric in Zbrush).
This was originally going to be a reskin for the Athenians, but since Athens shares most of their units with other hellenic factions (except Sparta) it will apply to them as well. I will get around to doing Epirus and Macedon's unique units as well and try to give them a more unique look. Once I finish off a few more clothing variants I'll release the first version, which will be all Athenian units except Archers, Slingers and Javelinmen, then I'll get started on Sparta and the others.