I wonder if this would fit the S10? comparing the pictures of this and pictures of the S10 tail light in many of the various pictures from Wasp's mods, it looks like it might work. It doesn't cost much to try at only $20.
http://cgi.ebay.com/ebaymotors/03-05-Yamaha-YZF-R6-Integrated-LED-Tail-Light-Taillight-/290454247458?pt=Motorcycles_Parts_Accessories&hash=item43a06c1822
http://cgi.ebay.com/ebaymotors/03-05-Yamaha-YZF-R6-Integrated-LED-Tail-Light-Taillight-/290454247458?pt=Motorcycles_Parts_Accessories&hash=item43a06c1822