Custom WordPress Site

I am looking for a WordPress site which will do the following. Will have 3 User Groups 1 - Enquirer - This user can register for free and can fill out a form to generate a quote request. The user should be able to have several quote requests at the same time. Should an operator complete a quote request the user should get an email as notification. If Enquirer likes a quote, they can accept it and no further quotes will be accepted 2 - Operator - This user can register but will have to pay a monthly subscription via paypal to access the account. There will be some automated filtering but they will basically see a list of quote requests and can then provide a price and some comments and a reference number as a quote. Based on the filter if a new quote request has been created, the operator will get an automated email. 3. Administrator can see everything and can delete quotes or quote requests if they seem inappropriate. Can also ban any user User groups 1,2 will only have frontend access and shouldn't be able to access the wordpress dashboard. Frontend login / registration and paypal integration can be done via existing plugins but anything else should be contained inside a custom plugin. Forms and lists should be added via shortcodes to the frontend to make it easy to switch themes. You should be able to switch themes without having to do any coding at all.