Here are photos, kindly sent by Chris, of his RP1 on his Thorens.
It is using an SME adapter, ostensibly for Ortofon arms, which comes from Hong Kong.
The ebay link is here. I have also seen them advertised in clear anodising (silver finish). Another black option is here
It looks good and isn't too expensive. As a finishing touch, an option is to paint the silver knob black, or get a gold plated one.