Office 2016 has a search field in the ribbon for quick access to commands that may be hard to find.
Can such functionality be added to the telerik ribbon ?

Declined: We consider this functionality to be an Application logic as the information that need to be displayed is based on the UI(the defined options/buttons in the RibbonView). Also the keywords for activating a given option may be different based on client preferences or language. This functionality can easily be achieved with a custom Style for the RadRibbonTab, containing only the control which you will use for the search (RadAutoCompleteTextBlock/RadWatermarkTextBox e.t.).