A solid bar (vs. a cable) looping over the toe really makes a big difference. While looping the metal cable through the skins and placing the bar of the ski is a simple solution it seems like it will wear on the skin fold over time.
I found a very simple solution costing less than a buck or two using the Black Diamond cable loop attachment. Leave the metal bar looped throught the skins as it is intended. Get some PVC toilet water supply line (very thick, just the right diameter, and just a few cents). Cut a slit in the pvc tube lengthwise (be careful, use a sharp razor knife, and stabilize the tube with something other than your hand, i.e. a vice). Don't worry if the cut spirals a bit as that just gives more reassurance it can't come off. Cut pieces of the tube the width of the ski tip where it will cross the tip. Force open the slot in the tube and thread it onto the cable.