Worth a call to Pyramid Plastics. While they don't list the SS on their model list, the do list the ST and monsters, so maybe the SS is not far off. Pyramid make a product called Fenda Extenda, which is probably what you're after. Take a look here:
http://www.pyramid-plastics.co.uk/extenda_fendax.html If you want noise and road legal, the choices are slim. The best would be a road legal exhaust that has removable baffles. The road legal E-mark stays on the exhaust even with the baffle removed.
Arrow do them in a low and high version.
Website is here:
Arrow exhausts