Rolf,
My first thought is glass reinforced polyamide 6.6
It comes in rods, tubes, plates and blocks.
Since this is just a thought, I don't know how much compression is there on the foot. The GF PA6.6 has a tensile breaking strenght of 150MPa dry and 140MPa wet.
Any ideea how much compression should it take ? The PA is lightweight -1400kg/cu meter, 2x times lighter than Al.
Very curious about the compression forces there.

There is also carbon fiber reinforced PA, and glass reinforced PEEK and carbon fiber reinforced PEEK. But GFPA6.6 is the least expensive.

Anybody good with the numbers ?