Simple Social Network

We need to create a new social networking website (similar to Twitter) using Drupal. This will mainly involve integrating several contributed modules, and customising them with CSS. The layout would be similar to this existing Drupal site: [login to view URL] What we’re aiming for is: - Customised registration and login forms - Customised user profiles - Status updates, activity feeds, friend lists (using a selection of these contributed modules: [login to view URL]) - CSS valid according to [login to view URL] and HTML valid according to [login to view URL], and have WAI grade ‘A’ accessibility - Firefox compatible (IE compatibility not necessary)