Business Cards Website Needed

We are looking to build a website similar to vistaprint, overnightprints, [login to view URL] and other online printers, to be able to accommodate heavy traffic and load. The design will be done in-house. You will only need to write the engine and integrate in with the styles. The new business cards website needs to have streamline process to create, design and print business cards. This includes online designer, upload ready designs, generate print ready PDF proof, online payment processing through Paypal, [login to view URL] and similar payment processing systems, customer base as well as integrated with other websites that we operate. Other than designing business cards the online designer piece should also need to be adapted to design t-shirts prints. The system should be scalable and easy to operate from the backend, coupons/discounts, customer management, integrate to quickbooks, as well as other. All content should be easily configured for SEO. The code should be written well with comments (English only) and should be easy to transfer to in-house programming team. Only looking for experienced with very similar projects. The bidder should demonstrate the ability to complete the project. In your bid please state at least 3 of similar projects you have completed in the past, as well as which CMS (if any) you propose to use and why. Potential for ongoing work if proven successful. The winning bidder should be willing to communicate effectively through Skype, phone & email Looking forward to your bids!