Toolbar or custom made widget

user001

I want to build a task bar with bigger image buttons, just like (or exactly the same as) the Qt Creator left most vertical button bar. It will be nice if it can expand when there are sub-items. This may be next step.

But

first I want to know is that a QToolbar or a custom made widget. Any similar example/code available?
I have QToolBar version available now but don't know how to change icon or make the selected one different with others in color or ....
If want to make my own, can I start with QToolBar by adding buttons on it?