Development of site like example (no design)

We need to have a website built that functions similarly to the site http://www.etsy.com. NOTE: This project request is for creating the functionality only. All styles and design will be done by us and should not be included in your quote. The site we want to build has a similar architecture in that it will allow people to become members, customize their page (minimally) and upload items to sell. The focus of [login to view URL] is more crafts and homemade items, whereas the site we are creating will focus on fine art and gallery pieces. [login to view URL] The middleware and backend for the site will preferably be built on Joomla and use a MySQL database. The front-end for the site will be built using predominantly a web standards compliant Javascript framework like JQuery, but data should also be exposed via an API that supports XML or JSON Objects as it will also be consumed via Flash/Flex, Objective-C, etc. in future projects. Please include relevant work samples for your quote to be considered. Thank you.