Add-in Express allows you to start writing an add-in in just 15 minutes. You create your own toolbars and place onto them: buttons, edit boxes, combo boxes, and pop-ups. Add-in Express correctly handles hiding and deleting controls, as well as moving them to other toolbars. It also allows handling the controls' events.
Quick Demo project includes the source code of a sample COM add-in for Excel that shows the use of Office Add-in Express classes and details of toolbar and control creation.