MaterialEditor version 1.4 adds the ability to change shaders. Switch to one of many shaders that come with the game, or use a custom shader. Included in the download are two shaders, the Goo shader and the BetterMatcap shader.
Both the Goo and BetterMatcap shaders support matcap textures. Matcaps are images that can significantly change the appearance of an object.

Matcaps look similar to the above image, like spheres. You can find thousands of matcaps by searching on Google, and even find matcap generators. Simply replace the Matcap texture using MaterialEditor after switching to a shader that supports it.
Version 1.4 also allows you to edit the material for the face and body. Due to the way they are handled, they each have a separate button in the Face tab of the character maker. You will need to turn on advanced mode in the MaterialEditor plugin settings for these to show. With this change, you can switch the body and face shaders to use the Goo shader, for example, and make your own goo girls.