Thanks a lot AR55 for the kind answer
I did find finally someone in France this summer who is about to make a pair for me with 40mm square metal tubes. We took the option of a slightly backwards bended stand. The design of which is attached (with a variant), dimensions in mm. The stand will be filled with sand from the upper two back tubes.
I have elected to take the first one with four sides on the bottom part of the stand for a better stability. They will be painted in black with some surface grain. Cost 163€ (approx 180us$). Not cheap, but this is what it takes. I should have them end of Septembre. Will post a picture by then.