If you want to add tabs to a workbook in Tableau Server, the following KB will provide info:
If you are talking about Tableau Desktop, the tabs cannot be moved to the top of the UI (they are at the bottom). However, if you can hide the extra tabs (i.e. the individual sheets that are on the dashboards). To do this right click on the unwanted tab and select Hide Tab. I hope this helps!
Hi - Joseph did you ever get this created outside of using server?