Build eCommerce Site (already designed)

I've designed an ecommerce website for office cubicles - I just need it chopped up and implemented. WHEN YOU BID ON THIS PROJECT,? PLEASE SAY? WHETHER YOU WOULD BUILD IT FROM SCRATCH, OR IF YOU WOULD USE OPEN SOURCE CODE (AND WHICH YOU WOULD USE). **Here are the requirements:** * Product Attributes/Options (that affect price) * Featured Product * Specials * Variable Shipping * Ability to Checkout or Request Bid * Store session before register/login (to store configuration of cubicle) * Charge tax if not in one of 3 states * Custom title & meta tags on all pages * Article pages (for SEO) * Secure Pages * Testimonials (AJAX display) * AJAX popover on product page * Admin area with CRM **The product? selection and checkout? process is about? 5 steps:** 1. Choose a cubicle size 2. Choose fabric, trim, and work surface 3. Choose configuration (4 pack, 8 pack, etc.) 4. Choose accessories (storage bins, lights, etc.) 5. Request a bid or Checkout