There pretty easy to make if you able to.
I'm currently doing one now. Alloy plate from eBay 400 x 300 x 5mm and the spacers to suit my tenere all for �31.
Just the longer bolts to buy and drill holes in plate.

Here's a site that I was thinking of using for buying a new one.

http://www.altechdesigns.co.uk/yamah...gage-rack.html