It can and has been done. Problems arise in a few spots. Typically, the turning radius on a snowboard is super short compared to skis. So anything you mount like this will be super turny...like too turny.
This can be remedied by using alpine boards. Coiler has a 193 GS board that is awesome and has a pretty long radius. The problem here comes from the stiffness of the board. Because you are using 2 feet on a board that are spaced out towards the tip and tail, the flex profile of a board is much different than a ski. The beef of the underfoot stiffness extends much further from core center than it would on a ski. So mounting a binding in the middle wont give you enough power to utilize the sidecut of the snowboard, resulting in one scary ass ride.
So yes, it can be done, but unless you designed a custom snowboard to make it work well with sidecut and flex pattern (aka design a ski) it doesnt go far beyond the novelty factor of having 2 boards on your feet.