What about if you need to have normal mapping an possibly gloss mapping for each texture? Won't that reduce the number of materials you can use per chunk drastically? I do multiple passes on my chunks, works great and means I have no limit to the number of textures per chunk.
What you mention sounds very intriguing do you mind explaining it a bit further?
He means he redraws the chunks of terrain multiple times using different textures and material parameters instead of trying to pack all the data into a single draw call.