Yes it definately is! It's atributes are the same as the unit in the diplo slot. You just create a unit in the diplo spot and give it to the barb civ.... than there you have the barb leader. He is the very last unitgfx in the unitsfile.
In order to get the Barb Leader pop up text, you have to have the unit in the diplo spot be either a settler/diplo/ or trade unit.
-FMK.
__________________
It's a wonder that you still know how to breathe.