Build a customer support website

We need a customer support website built with the ability to offer the platform as a service to companies who want to provide personalized customer support. So it will have multiple companies as clients and each will be able to use the platform for their own site. It will need the following features (feel free to use 3rd party software): 1) Live chat feature 2) Help desk type support (person leaves a question then the client answers it on the board later and it saves). 3) Question and answer (automated feature you see on many websites where a person enters their question and the system pulls up all the pre-entered answers that match their description. 4) Community (like a forum where people can come and chat. 5) Couple basic html pages like contact info, faq, and advertising info. 6) Announcement feature (pretty basic just needs to leave an announcement up top). for some examples see: [login to view URL] All of the above features should have the ability to be enabled and disabled by the client at anytime. If possible and we're open to suggestions here we'd like to be able to somehow integrate the design to the customer's website (maybe change colors and add their logo to their panel).