I figured the easiest way to make a metal oxide resistor would be to fill a tube with iron oxide and put wire in the end. I did just this. A got a short length of 3mm OD glass tubing, placed a peice of 14AWG copper wire in one end, poured powdered iron oxide (made from steel wool) into it, and placed another wire in the other end. When I connected my meter I discovered an annoying fact. Iron Oxide (FeO2) is completely non-conductive. I think after that fail carbon composite is my best shot.