I want the basic functionality of [url removed, login to view] (except that pulling content from just one account is enough) that is built on Drupal, Joomla or other accessible CMS that allows for people to register, comment, share etc. System must be able to for example highlight the most retweeted posts and should also do rudimentary semantic analysis of the tweets like paper.li. The use case will be a very specific one, so this should be easier - I will give you examples later. You will also need to able to modify RSS feeds into Twitter posts.
Account system must have FB+Twitter integration. There will be a couple of blogging modules also.
I will need you to install up to 20 instances of the system. I will either give you modified templates for this, or if you want to include slight template customization (header, fonts, colours) in the bid, please indicate this (but don't put too much weight on it as I can do it myself too).