The perlin noise texture is simply a non tilable (at the moment) texture, and passing parameters to the function is possible with a few tweaks, to change the outcome of the generated noise, for this demo, it is basically hard coded values used, as well as a fixed texture dimension (1024 by 1024).
ScreenR Demo: [ScreenR]
Screen Shot: [Google Docs]
Github Code, Project (PerlinNoiseMultiTexture): [GitHub Public]