I got a Mod to that effect made I had high hopes for it but I found that durring run-time the game would switch unit back to their default UnitMeshs. I'm not shure if it will ever be possible to overcome this limitation without getting into the linkages between the exe and graphics engine. If anyone is interested in continuing it as their own project I can bundle up the existing code and make it avalible. The Mod works by loading a new XML file called FlavorUnits.xml which contains "Flavors" which are named groupings of UnitType-ArtDef combos, these are loaded into a new Info class. Each Civ can reference a Flavor on its CivilizationInfo.xml, as the game runs the flavor of the active player is tracked and the getArtDef function is hacked to redirect to the replacment data. It works but not consistently and I dont know why.