Here's a quick idea for those wanting a bit more control over the final look of your sculpt if rendering in sculptris. Paint your object as normal, texturing and adding bump where you want. Once this is done clik options > save image and it will render out what you have there at the time. Then simply change the material type and save the image again (perhaps describing what kind of pass it would emulate ie image_ambient).
After you have multiple images saved open them in photo editing software (gimp is completely free if you want the free route, in this case I used photoshop but most photoediting software comes with the ability to add layers). Using layer types you can then start combining your rendered images in to one. Ideally start with a flat texture /ambient pass on the base layer adding different ones on top. Some materials emulate rim lighting and such which can be to your advantage, others may offer some nice specular properties. You can also mask parts of these to get the ideal look you want.
Below you'll see a simple sketch on a sphere with some texture and bump added, along with the passes used to create the overall image.
Above - the final composited image. I used the rim light render last and duplicated it to get a nice crisp edge where I wanted it. Rather than a completely flat ambient pass I used a 50/50 pass which just adds a tiny bit of depth to increase the texture.
Below - The 4 passes used Left to right, rim and specular, Kicker, key and ambient (50/50 pass in this case).
Give it a go anyway! All of this can be done with completely free software such as Sculptris and Gimp. Enjoy!
Sculptris: Using different materials for a multi-pass render alternative
