These were common with Oxy/Acet cutting before Plasma cutters and CNC tables. Many a hot rod hit the rod because of them. I have an old American Hot Rod magazine somewhere with plans and I think Popular Mechanics also published some.
Thank you for the link to those beautiful plans, the update to modern materials will make a huge difference in performance. Still a most useful addition to a workshop and takes up far less space than a CNC Plasma cutter table!