TFS Kanban boards are cool. They have some great features. My biggest beef has been with the lack of integration with the TFS data warehouse and reporting options. In my video "5 keys to producing reports for your TFS Kanban" you can see what options are currently available. The main one that I have found is a tool Jeff Levinson from Microsoft has created. It uses Tabular Analysis Services to help you create reporting data. Use this in conjunction with Excel and even Power Pivot, and you are creating ad hoc reports from your TFS kanban board. Check it out!