I have a rattle in my rear Mavic Ksyrium elite hub. The Dura Ace 10-speed cassette appears to be loose even when fully torqued to specs.

SOURCE: dura ace sti hangs on middle cogs on cassette.

change the cable ,because the have damage in the middle,

SOURCE: Can you replace the rear Campagnolo 8 speed

yes

SOURCE: Ksyrium Elite Wheelset: Raced this morning on mavic axioms and the hubs we...

Bearings. Take it to the Bike Shop.

SOURCE: I have 2006 mavic Ksyrium elite wheels having done

Could be the sealed bearings, just like a car, nothing gets better by itself if it is loose. With expensive wheels, take it to a shop unless you know what you are doing and have the proper tools. Why mess it up so that no one can fix it? Yes, I own 4 large bike stores and sell over 5000 bikes a year, anywhere from $325. to $12,000 models, so I do speak from experience. People are always amazed that the bike sometimes needs a tune up, Well, your car needs it too, but somehow a sewing machine or a bike shouldn't have to? Hummmm, interesting.
Take it to your dealer and let him advise you, this is not a do it yourselfer. Don't be surprised if you need a new chain, they stretch.