Open source Tumblr clone?

Does anyone here know of an open source social network framework that can create a site similar to Tumblr? Some features I identified as key to Tumblr are:

  • combination of multimedia and social features (equally suited to sharing image sets, including animated gifs, as discussion via text)
  • Each user has a "dashboard" -- a feed that only features posts from blogs the user chooses to follow
  • User to user messaging
  • System of likes and reposts, with "notes" listing who and how many have liked and reposted
  • All posts allow metadata tagging, so users can search through posts for content of interest. E.g. if you want posts about Metallica, you can go to tumblr.com/tagged/metallica.
  • Users blogs are subdomains

Can Elgg be configured like this?