Develop & Design social/blog/portal website

We are looking for a professional development & design firm to develop our social/blog network/portal website for us. We need something that can be based on Joomla or WordPress but we're definitely open to suggestions on which platform is the best to be used for such a project (Some developers we spoke to stated this might need to be a completely custom project from ground-up based on something like CAKE PHP). We will have a lot of unique features and sections to the site that are interconnected so site needs to "flow". Site will be divided into continents and then countries and will offer daily news articles (manually submitted as well as rss feed from elsewhere), daily blog entries by our staff as well as guest blogger entries by prominent artists and political figures. It will also be a portal for various artists so we will need ability to sell products based on various country/categories that current user is browsing since we will have various products that we want to cross-sell based on country/nationality/political/regional issues/topics that user is interested in. Site should have full integration with popular social networks (facebook,twitter,pinterest,etc) throughout all website portions, from articles to blogs to products and contests, etc. Bloggers will be creating accounts and blog posts, communicate with the audience and have various polls/contests/etc. Artists will need to have the ability to login and upload their products and assign them to appropriate categories. Users should be able to communicate with artists and bloggers, be able to send counter-offers for various products to the owners, rate and comment on products and blog entries, pick favorite artists, have various contests. Products will come from user-submitted content, such as clothing, paintings, photos, etc as well as our product line which will be fed from external source. We have API access to the data so we will need to implement that into the shopping section of the site where users will be able to purchase our products as well as outside sellers. We will donate portions of all proceeds to various charities, will have various contests where users can weigh in on which charities to use, make recommendations. We will have other features that will need to be developed. After initial roll-out, this project will need on-going support to expand, improve, and implement. If you think you have what it takes to develop, design, and support such a project, please bid, send messages with references & portfolios and we can discuss this further. SERIOUS BIDDERS ONLY!! PLEASE READ PROJECT REQUIREMENTS BEFORE BIDDING!!