IMHO the only realistic long term solution is to get a firm to make up a batch of polyurethane ones like these (GXR1000/Hayabusa)...
I've already tried three companies in the UK and all have shown either a lack of interest or "that's out of our scope of manufacturing"! Maybe someone can try and make some enquiries abroad? I'm sure there would be a sufficient level of interest in such a product here on XT660.com?