i saw one on france ebay a while back but ran out of time to organise bidding on it when it was a ship to france only and no paypal auction which made it hard. Yeah it does look similar to XT 500. They clearly would have started with a TS 185/250ER tail light bracket and modified it from there. I will look at my 185 bracket to see if there is clearly just one major difference. it could just be one different bracket spot welded to another.
the reason for the big tail light was because of tightening ADR rules. the bigger light for visibilty, clear number plate light and to have a brighter globe. if you but a brighter globe in the rubber lights the lens melts!. got one in the mail today and the lens was melted in the center from the extra heat. Dont know wht they didnt fit a decent headlight to the front while they were at it instead of the pissy 15/15watt candle
Michael, dont go mounting one of these lights to your fender until you get that little bracket that goes over the frame loop ( see above photo) and also you need the big metal brace that goes under the fender to support the heavier metal tail light.