Creating or Cloning New Units?

Has anyone tried to create or clone new units. I've edited all the text files I can find--desc_model_battle, models_unit, export_desc_unit, export_desc_buildings(so I can build them, but I beleive that doing this was a mistake), and creating a new description of the unit in export_units in the text file. But I cannot locate the new unit to recruit it. Any ideas or info would be greatly appreciated. Also, has anyone located a file that describes the prerequisites for unit recruitment? I thought that it was the export_desc_buildings file, but now I am not sure.

I assume that CA will be creating an Editor for game, till then is creating units impossible (unit numbers hard coded)?