I was popping around to the silicone rubber suppliers today and was shown some of the new products they have... My main goal was to obtain some RTV for a project i'm working on, at the moment. I asked the rep. if he had anything that might double for foam rubber that has the softness of human flesh and can be painted.
Suddenly he pulled out of a box this pink blob of something, that looked like a sea cucumber in shape. I touched it and it was the softest material I've ever handled... you could easily squeeze it down from 1inch to less that 1mm. It had a dry surface to it but the core was very sticky but didn't leave a residue of any kind on my fingers.
At LAST I've found the material I need to make prosthetics and masks with rather than foam latex which is so costly and hard to work with.