Custom project management script

I need a script which has the following modules and does the things listed below. It is basically a project management script. 1) CLIENT submits a form to set up a project and makes payment by Paypal (IPN or API function required). This form can be one where the CLIENT is already logged in or on a public page (for new CLIENTS) 2) On successful payment, WORKERS with the right skills are automatically emailed the project or messaged on the internal system and can accept or decline project. MANAGER is automatically notified of the new project and the WORKER assigned 3) WORKER finishes project and the MANAGER is notified. MANAGER can choose to assign to another WORKER or send back to CLIENT 4) CLIENT is informed by email of completed project or by internal message. CLIENT, WORKER and MANAGER all have accounts and there need to be account functions (register, log in etc) There will need to be separate modules for the CLIENT, WORKER and MANAGER to see relevant details (e.g. see current project, see completed project, see status of project, see project cost, satisfaction rating, MANAGER manually create project for CLIENT, statistics etc). There will also need to be a PAYMENT module to track Paypal payments from CLIENT and payments owed to WORKER The above is just a simple version of what I want - I will send a more detailed spec to the chosen freelancer. If this can be implemented into a WordPress/Joomla/Drupal install as a plugin/extension, that would be good (so you can rely on the CMS user management system. INTERESTED PARTIES please quote my username when replying.