I like the idea of a
SW blue base but the bleached bone might be a ittle too warm/brown for that. I'd bet you could accomplish most of what you want just with the
SW Blue and Skull White and maybe use some greys (in place of the brown undertones in the model you posted). That might be too reminiscent of a mammalian corpse, but--hey--there's an idea, too. Ice Blue may also be worth having around--as seen on the wings of this
beastie.
Automatically Appended Next Post: Also, take a look at this Trygon:

I painted all of the flesh areas with Rotting Flesh. This was then washed with Thraka Green and then highlighted with Rotting Flesh again. Once that was dry I glazed it with Enchanted Blue before applying final highlights of a Rotting Flesh/Bleached Bone mix.
Source:
http://www.antipwn.com/paint/category/warhammer-40k/