Custom e-Commerce site

Yeti Works is currently looking for a new site built using C# and ASP.NET4. The site is needs the following front end features. * Main landing page - Needs to be attractive and editable for frequent marketing updates. * Page template - Used for creating extra pages. Commonly used for listing news articles, specials or hosting a specific auxiliary page. * Catalog - Self explanatory. We need a space to host multiple categories, and configurable products. * Products page/configuration selection - This page hosts the products and configuration details. The products are generally computers which have configurable hardware selections. * Contact form * Google analytic eCommerce tracking. (being able to track conversion using google analytics) The back end of the site needs the following features. * Product option template - This is used for creating and updating sets of product options. We would also like stand alone options. Templates will be used for mass updating. Each option will be accompanied with an image that rotates when the option component is selected and a expandable info box for extra option info. * Paypal pro and google checkout. Paypal pro for seamless onsite payment processing. * User and order management. * Custom invoice creator - for creating standalone invoices. * High level option class - this would be a type of option that changes the parent products image. Such as chassis selection. * RSS catalog feed. * Any other negotiated necessities. I require the code to be extremely efficient and easy to maintain. (Lots of comments and analytic design). We will be modifying and adding to the code ourselves for minor updating and will need something that is friendly. We can and will create a storyboard for the site, database for ease of coding navigation from whomever we choose. The site must must be written strict and have a clean commented CSS file. We will provide sources of design and flow inspiration as well once the project is started.