Progress Bar

I recommend both progress bars and loading/wait indicators. By wait indicator I mean like a spinning wheel.

Edit to previous comment, I think that is what you are calling a throber widget. Either way would it be possible to add the progress bar and possibly the throber widget to either the 0.3 or atleast the 0.4 release as targeted bugs?

As they are widgets, they don't need to be targeted to a release. If somebody implements the widget using the guide (http://sambull.org/program/sgc/dev.widget.html) then they can be added to the current release. The 0.3/4 release will be focusing on redesigning and improving some of the core underlying elements, while widgets can simply be added to whatever the current release is.

And, yes, the Throbber widget is the one you're looking for, though to copy GTK it should probably be called a Spinner. Also, like GTK, the progress bar should support pulsing, which might serve your purpose.

I'm a little busy to work on this widget right now, but if you want to give it a go, feel free to ask me any questions while working on it.