@Hagen
Giving the colour of the macedon Companian Cavalry to the greek ones is
very easy. Just go to the descr_model_battle.txt, search for greek_royal_cavalry and change the entry "texture greek_cities, data/models_unit/textures/unit_greek_royal_cavalry_greek.tga" to
texture greek_cities, data/models_unit/textures/unit_greek_royal_cavalry_macedon.tga...

That would work with the armoured (elite) hoplites as well, but there is no thouch texture for them... so you will have to make the texture yourself, I´m
affraid... How to do so can be read here: Guides, tutorials & tools