I recently tried to order a set of Yakima Whispbars but was told that the Fit Kit that attaches directly to the factory "bright" rails was out of stock and being discontinued.
I then attempted to get the Thule Aerobars, only to find that they've discontinued the fit kits that attach to the rails.
Finally I figured I'd look into the Mopar ones and, sure enough, they no longer list the ones that attach to the rails.
I threw my two cents into an ongoing thread at Jeep forum:
Bars for Flush Roof Rails - JeepForum.com
One of the commenters had this statement: "Thule has made this combination obsolete because of (as told by a local Thule distributor) vibration and stability issues with heavier loads when mounted to the factory rails."
I've never heard of the factory rails being a problem but something is up when the two major rack manufacturers stop making mounts for the rails. I figured I'd check on Jeep Garage to see if anyone here has heard about this problem.