Changing type of barbarian units?

[steve.wray]

Has anyone got any pointers on how to change the type of unit that barbarians turn up with?

I note that the unit type changes thru the game; can this be hooked into?

My idea is that in the modern age, barbarians are (ahem) 'terrorists'

barbarian infectors, spies, corporate branches (?) and worst of all eco rangers appearing within the borders of ones civilisation would be quite the challenge!