How would you recommend I light 2 pictures, one on top of the other, in a dark stairway? I would like to use 2 halogen lights, on to light the top picture and another to light the bottom, but would like to mount both lights in the same spot, one with a shorter arm and the other with a longer one. Does such a spotlight system exist?

Have never seen anything quite like I think your describing, and depending on where the lights are mounted and what level you are viewing them from, they might block part of the top picture. Something that might work is using a near flush-mounted light and a flat shade with a white or silvered interior to direct the light only at the paintings and out of your eyes. Just remember most lights get very warm! My boarder just burnt a hole in the wall of his room with a desk lamp, sigh! Good luck with your decorating