I have two D.H. stainless steel centre stands and asked Dave years ago about the possibility of getting stainless springs to match. He told me that he had tried and could not source any. He then lent me a spring which I took to a 'Manufacturing Exhibition' to show to various spring manufacturers with a view to getting a batch made. However, when I showed it around they all shied away from the job. My memory is that Dave told me that they are off Gold Star centre stands so there should be a market other than just Vins but if you look at the springs carefully you will see that they are a non trivial producti0n job. I could try again but my guess is that there would have to be an order of 50 plus before anyone would take the job seriously.
Once again if anyone does better then I did then I would be in the market for some as probably would Dave.