Test this extension here: try.jigoshop.com
Simply Jigoshop (former Jigotheme) is a clean and simple theme designed specifically for Jigoshop. It features a custom AJAX dropdown shopping cart in the header, custom menu areas for product categories / standard pages and a custom widget for displaying banners and other eCommerce specific content.
There are 8 colour schemes each of which are selectable from the WordPress admin panel;
Best of all Simply Jigoshop has been optimised for use on a wide variety of mobile devices from netbooks to tablets and smartphones.