GTK does not have a Rotary or Dial widget. I expect this is due to lack of interest/agreement on how it should be implemented. Such as how it should look, how you would interact etc...
This does not stop you from implementing your own widget to suit your application. This is done on many audio applications written using GTK such as Ardour and the many audio plug-ins and audio effects application.
Qt does have a Dial widget, but the look of it is very basic. As for OpenOffice I expect the Dial widget is probably a custom widget.
Hm, what about clutter? I did not use it, but i heard about this library