Good job, looks good
I'm on Windows right now so I'll try later when I'm back in Linux.
Would this also work on XFCE or only on Unity?
I believe the notification system is separate from them but requires libnotify-bin.
If you don't have notify-osd you can just do sudo apt-get install notify-osd.
(as a note it will likely work on many other Linux distros just not natively)