Check out my mod in the files section. The massive attack mod gives the 'light units' like Hobilars, Peasants, Spearmen, etc double the number of troops (like 120 instead of 60 and so on) - supply costs remain the same (so after you raise it the BIG problem is supplying them/paying them!!) but it does give you and the AI (historically accurate) peasant/light troop heavy armies.

Gilbert de Clare