It would be nice if there was a DropDownButton that could contain any drop down content instead of being an ItemsControl with a ContextMenu.
An example of one can be seen in Telerik's WPF control library
http://docs.telerik.com/devtools/wpf/controls/radbuttons/features/dropdown-button
The DropDownContent property is of type Object, so any UI element can be added to it.