Customize AppTheme Template JobRoller

We're looking to make several function customizations to either the AppThemes JobRoller or the AppThemes ClassiPress (whichever you think may be easier to implement the features we require). We do not have either of these installed yet, as we are waiting to see which one would work better. What we are looking to achieve in the end is a reverse auction type website, for people to post tasks (like [login to view URL] and [login to view URL]), and others to bid on and complete them for that user. User A posts a task they need done and the amount they're willing to pay. User B bids on completing this task (they can choose a lower price to do the task if they wish), and User A can award the task to a user. What we need: 1) A reverse bidding system in place for each task that is posted. User A posts the amount they will pay, and User B bids on completing this task. User B can only match the amount User A posted, or lower (they cannot bid higher). User A selects which ever user they want, which awards the task to that user, and closes bidding. User A and User B are now linked to this task, and when User B finishes the task, they mark it as completed, and User A get notified and must pay this person. We are planning to take a percentage out of every task that's completed, so our percentage would come out before the task completer is paid. This would also require a paypal integration, which is already available in JobRoller I believe. 2) User rating and feedback system. Each users profile will have a rating and feedback system. For each task they post, the other users will have to rate and provide feedback once the task is completed (and vice versa). This will also help for User A to select someone to complete their task, as they will be able to see their rating and feedback (same idea as eBays rating system, but does not have to be that advanced). 3) Private messaging system We want a private messaging system linked to user profiles, so users can contact each other if they wish. 4) Message board We would like a message board on each task that is posted. This way people who are bidding on completing the task can ask questions, the task poster can answer them, and others can see this as well. If you have any questions at all please do not hesitate to ask me. Thank you.