No, there has been no indication of a unit editor, either changing stats or graphics.

Some people have been making graphic mods on their own, but as far as I know, most of them have been stumped trying to crack into the .bif animation files. We hope people will post updates as they occur.

The battle editor may let you set things like starting armies and locations, but you are still playing with the Shogun and Mongol units.

-- B)