"It would need something more like a conforming semi-transparent second-skin."

There's the BodyMorpher figure for Posette by Staale Loseth whose .obj file was modified to provide a second mapping layer. The example 3TextureLayeredBox shows how he did it. AND, in fact someone created a nice looking wet skin  with her using the second layer and a transparency map IIRC. The thread may still be here somewhere. Since the .obj file incorporated the layer(s), that would eliminate the morphing problem. I'm not sure how practical a solution that is and I would have thought that with today's tech there would be better alternatives but who knows.

SkinVue for Vue does pretty nice wet skin. There was also a utility, perhaps called "dropper," maybe by Masa(?) that created tiny spheres on an object. For the ultimate realism, maybe something like that which  actually created geometry would be best, but that's a lot of drops :-)

http://home.online.no/~kjellil/Index-AllStuff.htm 

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken