I'm making a request to add a new notification method to the Window Buttons (tasklist) plugin. When in just icon mode (labels disabled) - I'd like for the notification of events to allow the icon to bounce up and down from the panel rather than blink, or possibly bounce a few times to get attention, and blink or stay lit up until the window/icon is opened/clicked. I'll offer a bounty for the addon/feature upgrade. Starting offer is $100 USD but am open to bids and can pay by PayPal. If you have any questions please feel free to contact me. I'm currently running XFCE4 on FreeBSD 10.0 but can build the linux xfce4-panel/plugins/tasklist/ plugin without modifications to code.
With gtk-css we could do more types of animations but not bouncing. And I really don't want to do cairo based drawing for this.