Years ago I had a different brand with torsion axles and needed to lift it. I purchased a lift kit directly from the trailer manufacturer. It was two lengths of steel tube and four flat steel plates with pre-drilled holes. The axles were unbolted from the frame, and the flat plates bolted in their place. The tubes were then spot welded to the bottom of the frame. Finally the axles were bolted to the second set of holes in the plates. This was a 4 inch lift as I recall. Any good welder can fabricate the needed parts, just no welding to the axle assemblies, bolts only.