We have seen the SpaceNavigator from 3DConnection work with Motion for flying around in a 3D composition. This is a SpaceExplorer controlling Final Cut Pro. The quality of the video isn't great and it's a bit hard to work out what is going on, but we are up for anything that gives us more control and speed when editing.
Apple officially supported the SpaceNavigator when Motion4 was released, it even made the Final Cut Studio 'What's New' product page. We have never used it but we do know motion artists who love the extra axis control.
Now it looks like 3DConnection are proposing the $299 SpaceExplorer as a controller for Final Cut Pro. We've been through a few controllers here, jog wheels etc but for us using a tablet and a pen has proved to be the quickest way of slicing and dicing. That's not to say that something won't be better, the SpaceExplorer does look pretty cool and it will be interesting to see if any of its extra features will really help with FCP. We would love to hear from anybody who actually uses one of these when editing.