Great question !
I would love to be able to shoot my D4S more quietly as well, but IMHO anything that goes in direction of wrapping or housing the body isn't practical in the field.
That said, I regularly made the observation that the animals tend to be more affected by single shots or slow series while if shooting with full speed 11 fps. Of course this strongly depends on the kind of animal, but it seems to have something to do with way they interpret the noise. A single shot might sound more like a cracking branch, while a 11 fps burst goes more in direction woodpecker
. Of course the silence of a ML body would be best ...
One thing I seriously thought about was adapting the noise cancelling technology used for headphones. Just a little unit sitting on the hot shoe of the camera body with a mic listening to the shutter and then playing the recorded sound 180° phase inverted towards the critter. No idea whether something like that could work, but I like the idea ...