i was thinking the same thing, but the problem is that i don't think the bull bar itself would take the strain of the winch and added weight.
my thoughts were to make a bolt through bracket assy that goes through the front chassis support under the radiator, using some scaffold and 8mm plate.....
should get a good bit of strength from there, plus the winch would then act as part of the chassis, AND get the leverage it needs...i.e direct onto the chassis and axles...nice and low.....