if you select all of the faces in Edit mode and then use Alt+e to access the Extrude options menu->Individual.
Press the Esc key to cancel the movement.
Next, press Ctrl + i to invert the selection
Press x to access the Delete menu and select 'Faces'.
Now you should be left with only the extruded faces and they should be all separate components.
OPTIONAL:Personally, I would bake these results to a UV map probably using the 'Lightmap Pack'setting.
This way, the individual faces can be re-joined after baking. This helps keep the Outliner clean. The 3D Viewport should also run much faster when many Objects are joined together into one.
Make sure that everything is selected and press p to access 'Separate->By Loose Parts'.
Now enter Object Mode and make sure that all the separate pieces are selected then use the shortcut Ctrl+Shift+Alt+c
to access the 'Set Origin' Menu. Choose the option 'Origin To Center Of Mass' and now the model is ready.
The 'Node: Input -> Object Info -> Random' is key here. This is why the faces are all separate objects. Random greyscale values will be assigned to each separate model and this can be used to modulate the colors ramp so the color transition is a bit more scattered.
Here is a simple node setup that uses the random node to change the relative brightness of triangles.
This next node setup uses a second color ramp combined using the Linear Light Blend mode, many of the other blend modes give interesting effects as well. This setup also uses a noise texture to modulate how the main colors transition across the model.
Here's the .blend file http://www.pasteall.org/blend/35306