Create support for service provider

I need a business management site for service providers. 1. Role based logins clients, technicians and managers. Multiple businesses in the future must be thought into the database design 2. Contract management, creation of different contracts, with different services, that are automatically billed each interval set in the contract terms (Multiple contracts) 3. Time sheets, and handling of expenses/materials, think of stock control in the future 4. Task management for technicians, including updates to clients (digest emails) 5. Invoice generation, using hourly cost defined in contract, PDF and/or csv 6. Audits of client systems, where several points are looked into (possibly defined in contract, where each point can be added on the fly) 7. Stats of technicians, how many jobs per month, simple first We need this done in PHP/MySQL. Successfully contractor will have to deliver part and receive part payments on delivery.