Hi there, searched high and low and I'm afraid I didn't have much joy. It seems that elastomers have gone right out of fashion.
There are a few factories out there who make them but you'd probably have to buy half a mile of it. You could try Rapid Descent Scotland who do replacements for Proflex bikes so they must have a source somewhere.
I got my fork to work again by greasing every pivot to within an inch of its life and experimenting with the elastomer by stamping on it repeatedly and boiling it briefly.
It works now, kinda, but don't quote me on that. And there doesn't appear to be a scrap of info on the forks anywhere in the whole wide world.