Just ordered one of these at $60 CAD of ebay. Will post a review once received.
http://www.racediscs.com/Products/Brake_discs/Gas_Gas_RD_Discs.html#.U-wDmmd0zIU
http://www.racediscs.com/Products/Brake_discs/Gas_Gas_RD_Discs.html#.U-wDmmd0zIU