Online Training Portal/eLearning System

We'd like to receive quotes to build an online training/eLearning portal/system. Here are the high level requirements: * Need to be able to upload and host the training modules (content is video + slides) * Users login in and see their available modules and progress * We need a testing capability that records their scores from a series of questions at the end of each module * A way to generate a personalised certificate and allow them to download * Take payment for accessing modules and allow access accordingly (prefer PayPal) * Promote upcoming modules * Present a bio of the author * Ability to view sequentially or select specific sections * Ability to download course tools in the form of documents * Suggest improvement or features We would prefer to do this in Ruby on Rails but am open to other platforms (non Windows preferred). You can either build the system from scratch or preferably adapt an existing system. Applicants must show history of building similar systems/sites. You will be working with a website designer to incorporate the graphics side of things. We will pay on achieving milestones during the project & prefer not to have to pay anything upfront.