Jay, I think that putting a border of stone around the bottom would make a nice accent to the wall. What are you planning on using for the stone? There are companies that make brick/stone veneers that are applied to exterior walls. They would probably be a little thicker than the siding you are using. Just make sure you put a flashing that runs at least 3" up the wall under your siding (with the house wrap over the flashing), turns out over the stone , then down 3/4" with a hem on the exposed edge.