The .productListing-data selectors the op is using work, although in that case the dotted line messes up at the joint between elements.
Unfortunately, it is apparently not possible to give padding or border properties to table row <tr> elements.
The double dotted line is not a standard CSS border-style, so you will need to create your own if you want that. Make an image gif of the double dotted line with transparent background, say 100px wide x 5 px high, save it as /includes/templates/your_template/images/dbldotted.gif, and use that as the background for your products.
Code:
.productListing-odd, .productListing-even {
background: url(../images/dbldotted.gif) bottom center repeat-x;
}