You might look into Ecommerce Templates -
www.ecommercetemplates.com. I am a user of their products and found them to be rock solid. They have a very good support group and many first-time website owners. They have a good variety of layouts and designs and everything is fully customizable. You also get the full source code so you make any chages you like
Let me stress that I am not an affiliate. I just like the product. I have used it on several sites and even made extensive changes to the internals. It still runs great.