Good news and bad news. The good news is I have a solution for you. The bad news is that it isn't a shortcode.
The fastest and easiest way to accomplish what you're wanting to do is to use a PlugIn like
Create a page and call it something like "Inventory", set it as your homepage, then use the Redirect PlugIn to redirect it to your inventory listing as http://yoursite/cars-for-sale
Long term we still plan to add a shotcode for inventory display, but there are issues with getting the template page to load correctly and I can't give a solid time frame on when this might be added. When I looked into it this morning I was hoping to add it into the next release but it has proved to be a little more complicated than I had hoped.
Give this a try and let me know if this method is suitable.