Create 1-page checkout for Existing Oscommerce website

The existing Oscommerce website is in version v2.3.1 The project is for creating a one page checkout for website. The sample 1-page checkout is [login to view URL] The functions should include almost everything in the sample checkout pages, except -- all payment is US dollars. -- worldwide shipping depending on country ( I will set up in ADMIN tool for shipping method for "United States" delivery with 2 flat rate shipping; For "Canada" delivery with 2 weight based shipping; For "other countries" delivery with another 2 weight based shipping ) -- Payment options ( Credit card and pay by Paypal ) You will design the checkout page to fit our website page and colors, fully test the checkout before moving to production. If you want to work on this project, please answer the following questions when submitting the bid: 1. Have you worked on the similar project before? if so, give me 1 or 2 samples very similar to this project. 2. How do you plan to TEST this new checkout process before it is put into production? The budget for this project is flexible, we want to have the best checkout process possible for the website.