According to my Manuel...
Accountant-Barbarian = adv_smart1.gif
Metaphysical Gastronomist = adv_smart2.gif
Kleptobrainiac = adv_smart3.gif
The Mastermind = adv_smart4.gif
That fits the pattern of the other adventurers. (1 = fighter, 2 = mage, 3 = thief)