While flipping through my piles looking for Seren Ironhand, I pulled out my box of Wargamers Digests, and realized that "Swords and Sorcery - In Wargaming" by EGG includes at least two images by Bell.  (Probly worth checking Magician's Ring too, though I don't recall any).

If no one else beats me to it, after the holidays I'll check to see if they're also in the OD&D books, and scan/post them (it's unlikely I'll get to them before Saturday morning when we leave to head east for Christmas with my family).