Is there another way to customise the PlaybackWpfUserControl control given that the class is sealed?

As a part of adding new functionality to our existing plugin I was hoping to create a customised version of the PlaybackWpfUserControl, but found that the class is sealed. So is there another way to create a Playback Control (preferably WPF based but not essential) that has the same look and feel as provided in the Milestone client Playback?

I suggest you make you own control and then implement the commands the same way you see in the Video Viewer sample.