...I have the notion of using saw dust (crafted from the sawdust block) in order to alter the appearance of the top face of grass/dirt blocks to give the impression that the grass has been worn away or that bark dust has been placed on the grass in order to indicate a foot path. As with redstone dust adjacent "path in grass" blocks would link up forming a continuous path.
The idea is to have a cheap way to create a path without mining cobblestone. It is for aesthetic and for practical (pathfinding) value. Cobblestone and gravel could be reserved for roads. This would provide a nice contrast.
It looks like 1.9 is going to introduce Pressed Dirt blocks which would probably address my needs depending on the crafting requirements.