Today's experimental release (v1.26.9.0) brings materials rendering support to the Cool VL Viewer (and once more, the Cool VL Viewer is the first TPV to provide you with the latest, cutting edge feature !).
To see materials rendered, don't forget to enable deferred rendering in the graphics settings. Note that there are still many known graphics glitches, especially with bump-mapped, shiny and/or full bright faces.
You will notice a difference on legacy, bump-mapped faces already, but of course, you will need to find specular and normal maps textured objects to really see what the materials viewer can bring to the future SL experience. You will find a few in
Hippotropolis (though, among them, only the flat, normal-mapped white panel and the fruits (especially the oranges) are spectacular enough to clearly notice the differences... don't hesitate to modify the sun light position (via "World" -> "Environment Settings" -> "Environment Editor") to see how it affects the textures). Better objects will no doubt soon pop-up into SL.
I for now did not implement the new face/texture editor panel in the build tools floater, since the current implementation in viewer-materials is known to have issues that can lead to corrupt the edited prims.