Yup! It isn't an easy job to search the pu box especially 75.
You might still stand a chance for 79 box. I have been searching this box coming to about 2 years now. Do find some over at Australia but the shipping and handling is a killing machine.
BTW, emailed to proffitt some time back. US3500 is their selling price for the box.
Yeah your not kidding I have a better chance of turning a Rolls Royce into a off road rock crawler than finding a HJ75 bed.
Think I will start planning a flat bed design with off road in mind, thanks for the inspiration. Take care.