Hein Gericke used to sell them at £2.99 each, but they're not in the catalogue any more. I believe they're the same as Triumph ones?
Just did a quick ebay search - same as some Honda fitments!
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=400014073013 and for Triumph Speed Triple, T509, 955 955I.
or
http://www.fastbikebits.com/acatalog/Indicators.html