Design Tool for Custom T-shirt Online (E-commerce)

Hi, I would like to offer my online customers to design t-shirts, sweatshirt, hats etc. on my web site. This will allow them to add pictures, text etc. [login to view URL] offers a good one based on osCommerce. I can also work with Magento (or any other good open source e-commerce). Please visit [login to view URL] to see how the front-end and back-end work. It need it to be just as good and user friendly as CraftShirt. The winner of this project will get more work (paid) when the project is completed. I've many customizations I want to add, but first I need to have a similar store to start with. Thank you.