http://www.bhg.com/decorating/arrange-a-room/ is a user friendly online application that allows the user to select the room(house) size and drag and drop various items to visualize an interior design of a small space. It is on the Better Homes and Gardens website and it's free with no registration required. You can save and print your custom design interiors. It is intended for room design. But, it appears to be perfect for getting an idea of any small living space's layout and interior.