Rare for sure and expensive. Was made in carbon fibre by Chris Barnes in the UK but he went quiet and I think there were a few payment glitches. Good guy.
Hyde used to make a plastic version that velcro'd on - I managed to lose both sides. They don't make them anymore.
There is someone in Oz that used to market them reasonably recently (in 640 time about a year ago). But expensive. Last resort is to make up your own. I will order a set if you get a mould done.
