Magento Import and Customize

Bidders, We are searching for someone that can import 50k Products into our Magento store with images their are 5-6 different categories. (All products are already in CSV format from old database) We will also need to add Label, Artist and DJ Signup's using Username (Username must match name from Joomla site if the user-name is not found they must register on the Joomla site first) from our Joomla Site where the user can add there products to our store to sell. Users will be entitled to %60 Commission and the store will get %40 commission. The User, label & Artist will have there own My Account page to change products and monitor commission. (There maybe a solution for Magento already made, if so please let us know and include that within your quote) The DJ, Label & Artist must agree to a disclaimer prior to adding there Music or CD disclosing that they are the owner of said tracks. The Magento store must also be bridged to the Joomla site using the Magento + Joomla Bridge Component. This project may lead to other developments we have if work is done to standard and completed within the time frame stated. Please add MAGENTOEXPERT in PM to make sure you fully understand our listing all copy and paste PM's will be ignored. NEXT PROJECT: If this is possible the next project will be adding the users products from Magento to there Jomsocial Page and Sobi listing in Joomla site. (Separate Project) Thanks,