I built some new speaker stands to get the 4343s off the floor a bit. They're designed to resemble L91 lenses and are about 14 x 24 x 6 inches. The lense effect is simply some 1/4 in grooves cut about 1/4 in to the 1 in MDF. The inset is a 45 degree wedge, leaving 6 inches on either side.
Here are a few pictures: