---------------------------------------------------------------------
I can't help you directly but maybe you would find that the words Speed Mover may help you in your search. In case one of these would work for you, there are thousands of these that were just used to build a pond and spend the remainder of their life rusting away out in the pasture. Most of these may be too large for your tractor but on occasion smaller versions can be located. Good luck in your search.
Why do you think that a box blade will be less efficient for your job? I find that my box blade works very well for digging and moving a lot of dirt. Steve