Digital music store / website based on flexible CMS

I am planning to launch Digital Music Store / Website this is the detailed website description: [login to view URL] Music script - you have an option to either modify the music vendor script ( see specification ) or to build the script on your own, but it should have all the features that music vendor has ( so file security, pay pal, automatic delivery, mailing list, stats e.t.c ) plus I would like this shop to be able to add Coupons/Discounts to specific products, CMS - I would like this to be based on Joomla because it has lots of great features and modules, some companies say that Joomla is slow e.t.c , I am happy for this website to be on other CMS as long as I will be able to edit the website in as much detail as I like, for example adding/removing pages adding blogs with comments , forums, social networks e.t.c so please specify how are you planning to do this because I would like to add pages, blogs e.t.c myself which Joomla allows me to do SEO - One of major concerns for this website is SEO, I would like it to be optimized for SEO as much as possible and I will be more than happy to work with company that does it, because in the future it will be my major concern Overall view - so to keep this short this website should have search panel funcionality similar to [login to view URL] and the search results similar to [login to view URL], should be based on logo privided by me which should match with your design/layout, should be flexible and easy to operate (see CMS above) and search panel and results should be instictive Who I would like to work with - I will be more than happy to start working on this with anyone that will address all the major points of this project in its proposal, I would like to see how are you planning to develop this project, stages, ideas, solutions e.t.c so the more information / ideas you could provide the better for us thank you