I built 4 tall stands (range is 24-48 inches) out of 2 sizes of schedule 40 pipe (1 1/2, and 2 inch) 4 steel 14 inch rims, then used 3 pieces of 5/8 inch rebar to go from the outside edge of the rim to the outside pipe for stabilization. I used 1/2 inch pins for the height adjustment with holes drilled every 2 inches. I've used these to hold up my dually when I converted it from steel leaf springs to 4 link air ride. Empty the truck is in the 6,000# range. I'm very confident that they'll hold double that weight because I over engineered them to hold up my dually.
No one made what I needed, so I made them myself. They could easily be scaled down to a shorter stand if need be, but I needed something taller than conventional stands. There is no car that would ever be unsafe on them.
While we're on the subject of cheapy unsafe jack stands, don't ever use these crap stands that came about in the 60s.
They're made from a stick of tubing split into 3 legs with a strap spot welded between the legs. I've personally had one collapse when I had the GP race car in my signature pictures stripped out before I put the cage in the car. No engine transmission or interior in the car and the stand in the car collapsed overnight when no one was in the garage. I came into work the next morning and the car was sitting on the garage floor.