Reliable and Stable Online Store (repost)

Our company is looking for an intermediate/advanced to expert web designer/developer for an online pharmacy selling about more than a thousand products. We currently have an idea how we would like the site to look like and have developed a jpeg layout on how the front page should be. Inquire and i'll email you a copy. It would be a cross between this site [login to view URL] and this [login to view URL] in terms of design and functionality. Site requirements: Front end- A log in page and registration would be necessary for customers so that records/history of previous transactions and purchases may be recalled by the customer yet anonymous purchasing should be embeded as well. Necessary images, price list, product details etc. will be given to you. A fast and secure email contact form. There should also be a "buy now" option besides the "add to cart" function for each product on display in the home page and each product page to lessen the steps of purchase. Easily update-able space for advertisements, featured items, bestsellers and promos. Clean URLs and SEO fully optimized. We need it to support international sales and shipping. The payment gateway must be suitable for japanese customers besides a Paypal check out. Back end- There should be an admin content management area much like but not necessarily opencart, drupal, magento or adobe business catalyst; where the admin would be able to monitor specific product sales/history, sales graphs and analytics, view customer database and their purchase/history, email specific groups of customers based on number of purchases conveniently change, remove, add, update products and theme/look customization. What's most important about this job is front/back end security,stability and update-ability. Our question to you: How long approximately will it take you to build it? How much would it cost? We need you to provide us the solution. We are looking for the best creative solution and it can be phase approached. Depending on your Bid/Time Frame, we can pick most critical features first and add others later. Skills Required: PHP, MySQL, JavaScript, jQuery, Graphics/design, (Highly knowledgable in)eCommerce, Shopping carts, CMS integration. Please include work samples. Please respond only if you can remain in contact with us as our past experiences have shown that this may be a problem. Additionally, we will not pay a significant portion upfront but will create milestones so we are sure the person we hire is capable of doing what we need. Note that we will not select the bid based on quotes in and of itself. Others include past portfolio record and time taken to do the job. Skills Required: eCommerce, Shopping carts, CMS, PHP, MySQL, JavaScript Etc.