300DT trailer hitch ideas?

1984 300D turbo, 123 body. I want to hang a flat steel bar with cut-outs on the rear bumper shock absorber pipes. (I don't want to use those bolts for several reasons.) This bar would take some of the downward force on the trailer ball, hold the hitch in the center (left vs. right), yet still allow the bumper to move if hit. Then a strong hitch bar or square pipe welded or bolted to that, continuing straight under the spare tire with a T to the chassis frames on either side behind the differential. The latter would take all the pulling force. Any problems with this? None of the trailer hitch people here want to touch this car. Too weird, or not worth their time, I suppose. Ideas, please?