Online T-Shirt Designer

I am looking for someone or a company who can (or has) developed a "make -your-own" custom t-shirt/apparel site like Zazzle, Spreadshirt, Customink.... This project must either be a complete e-commerce/custom design app. like the aforementioned sites or be able to be integrated into an existing ope source php application (for the e-commerce aspects). All functionality of apparel/accessory design needed: upload/browse images or select from clip art library. Text, colors, product coloration. Please include links to past projects and describe what would make your work better than others with similar skills in your post. Why would your t-shirt designer be the best solution?