line, salomon, and look bindings all have wide brakes which are designated for skis with waist width of 90 to about 110 mm.  even with wide brakes you'll need to bend them to mount onto waterskis.  they do work, a little.  i have spatulas of my own and the brakes will eventually slow the ski down, although its much more likely they'll dive into the snow and you'll end up spending time digging for the ski rather than chasing after it. the key thing is to bend the breaks AFTER they've been put into place between ski and binding.  if you bend them before, very high chance they'll break.  u dont need an insane depth of snow for them to perform.  not only would they (hypothetically)float better than all skis, but the range in movement, plus control, is dramatically increased. this is cuz u dont really turn/carve in the deep, you slide across the snow.  you can still carve in deep, but once you learn how to slide you wont go back.
i say go for it.  you'll probably be pleasantly surprised.