I keep a lookout for new airliner conversion sets, decals and kits. Though 1/200 is not my scale I still look out for it. As you would be aware 1/200 is not as mainstream as other airliners scales and Military types which attract a lot more attention when it come to aftermarket stuff.
I have seen plenty of people 'roll their own' flap/slats sets in 1/200 and 1/144 because there is no aftermarket around. As I said above I have only seen one set in for the 737NG in1/144 which is available from Contrails in the USA and a set for the C-17 by Wolfpack. Even a search of Shapeways gives no Airliner wing/flap sets. To date, I have seen no 1/200 flap/slat sets around.
I am happy to be corrected if you can find any sets for 1/200 (and other sets for 1/144)?