Sorry I don't have any spares and they'd be a bit of a rarity themselves. I lost mine on a ride years ago and hunted around everywhere but couldn't get one at all. Ebay would be the best chance these days though you'd probably be slugged for shipping from the US .
Barring that, the one in the pic is a piece of stainless tube that I sliced open with a grinder, rounded the edges off and drilled some mounting holes in it. it's done the job for about 6 years and doesn't look too out of place. Took about 2 hours from start to finish.