Ecommerce site design and build

We're building an ecommerce site and we need some help. A lot of help actually. We want someone else to build our site for us. Our project is relatively simple, but has a few rigid requirements. We don't care about the platform we choose - we'll leave that up to you - but it needs to meet some criteria, aside from the more obvious/standard ecommerce site things: - It must support bulk loading of products, and simple price updates. Our suppliers supply us with a feed for inventory and pricing that changes often, occasionally several times a day. We want to maintain a local file (CSV or otherwise) and upload it as changes happen to update pricing and availability. - It must support custom charges and fees, separate from product price and shipping. We sell some products that incur special handling or environmental disposal fees. Those charges can't be baked into the product - they need to be separate line items. - It must support both product categorization and tagging as a way to find products. - It must present well on mobile form factors natively, both phone and tablet. - It must support customer loyalty programs, preferably as store credit. This will be version 1.0 of our website. We're hoping that it will last 3-5 years as a platform and give us time to build a customized solution from the ground up for version 2. We're looking for help creating this website, as well as a partner to stick with us over the course of it's lifecycle and beyond. If you're selected and the project goes well, you can expect that we'll be doing work with you on a continual basis, adding features and improvements as necessary. Our ideal partner would be someone with experience designing and deploying websites with thousands of products. Our catalogue is large and growing as quickly as we can add to it. Also keep in mind that there are several platforms that would enable us to do most of this project on our own without outside technical expertise. We’re looking for someone to elevate our final product, optimizing for mobile as needed, improving SEO, and providing a design that sets us apart from other sites who took the off-shelf option. For this project, we'll agree upon milestones and set payment for each step along the way. Our budget is flexible and is based on return-on-investment. Are you a good fit for this project? We would love to hear from you! Please send along your details, rates, and a few samples of your work that you think are similar to what we're asking for. If you have questions, send an email! * Since a few people have asked: - We like Shopify, but we're not completely sold on it. It's possible that the customization we'd need would make it more hassle than it's worth. We’re kind of relying on your expertise to make that call. - We're not looking for you to load product data. We need a framework that allows us to do it ourselves. We'll tell you what details a product page should have then we'll rely on you to build something we can populate with our content. - "What kind of website are you looking for?" seems to be a popular question too. We're building a big, diversified store. Think Amazon, or Newegg. No, we're not asking you to re-build Amazon for $20 and all the fizzy drink and pizza you can handle, but that sort of website is what we're heading towards. Lot's of diverse product lines, and lots of products. That same sort of categorical breakdown of products, with attributes and tags. We won't be there on launch day, but we'll spend all our time and effort building up to it.