I wanted a nice, large model, preferably standing a good head taller than his henchmen, and preferably wearing something vaguely in keeping with the pseudo-100 Years' War look of the Bretonnians. I picked up some of the Chaos Warrior infantry from eBay, and slapped an Ungor head onto the body. Turns out it works really well, especially with the addition of some Beastmen Gor arms (the Ungor arms looked a little weedy). The huge axe I selected is a little more over-the-top than I was expecting, but once I dry-fitted it, I couldn't say no (though I did file down 50% of the spiky bits)!
(The Big Boss in between his henchmen)
On a miscellaneous note, while I like the heavily armoured Chaos Warrior look, with the cloak and the fur stole thing, this is an absolutely horrible kit to prepare. The mould lines run right over the top edge of the fur, leaving a lot of cleaning up and fixing needed.