Social Networking Website Clone

I want to build a website exactly like this one... [login to view URL] but with different features. This website is very complex and spans out according to different register types. There are too many details to list so please visit the website, register for an account (to see the backend) and bid accordingly. I would prefer to structure this website based on the Joomla 1.5.x platform to help save costs by eliminating the need to build everything from scratch.