Actually I build two racks to fit across the ski box, one in front and one behind the bindings.
Essentially each is two small pieces of 2X4, one on each side of the box, with a smaller 1X3 spanning the box . They are fastened together and wrapped in carpet. one is placed 1/3 approx. from front and the other 1/3 from back of box. I put carpeting on the bottom of the box and the racks fit quite nicely into small flaps I cut in the carpet. When you want to use the box for something else, I just lift out the racks and fold back the small flaps of carpet where the end of the racks fit in.
When the skis are base to base, they rest on the two racks with the one binding facing down and the other up.
Holds 4 pair of skis. Poles are slid under the racks or just set on top.
Of course someone always screws me up and brings a bag or a snowboard. The board usually fits easily on top of the skis binding side down, but ski bags are a pain. :-)