Sorry bud, but that wouldn"t work. The back wheel is necesary because it provides power (it would be really troublesome to put the motive power into the front wheels because they move) and it provides part of the triangle that changes to make the tri-cycle lean. If the front two wheels had an axis in the opposite direction (perpendicular to direction of motion instead of parallel with) the base would be able to lean, but it would be rather hard to have the wheels powered and moving in relation to the base. If you have any way to make this work or if I misinterpereted what you meant, do tell.