I've just finished one using a thick plywood cut. Its light weight. I've used 1 stepper, 1 dc and 1 servo. The gripper is the tough part and i'm yet to complete it. for the moment using a shovel kinda setup 
its a simple 2 -axis one. but i think i can add many axis with the comfort of wood. The wood was inspired by the popsickle stick arm. check it out. its cool