According to the Japanese .Hack website and dothackers, there is going to be a new .Hack series based on the new .Hack//GU games. The new .Hack series is called .Hack//Roots. It will start showing April 5th (in TV Tokyo) and will last 26 episodes.
Here are some links to the pictures:
http://gallery.minitokyo.net/view/213540/
http://gallery.minitokyo.net/view/213683/
http://gallery.minitokyo.net/view/213684/
http://gallery.minitokyo.net/view/213686/
For those thinking that .Hack//GU is the new games, IT IS. Repeating for those who didn't see, this new anime is based on the new games.