It wouldn't work for the larger ones, but I remember seeing someone use toothbrush handles for colored lenses before. He just ground (grinded) the handle into the rough shape of the lens, then polished it back to a shine.
I always thought that the same process might be doable using acetate screwdriver handles and they might be easier to polish since you could just sand to like 600-800 grit, then polish by dipping in acetone.
Just a thought.