This patch allows the vertical tab bar to show the tabs horizontally. (see Feature Request: Text Alignment in Vertical Tab Bar - ID: 3300461)
This is more a proof-of-concept than a release-ready patch.
1. There is no UI option to revert back to vertical text. However, code-wise it is possible by setting a boolean value, so it is just a matter of adding the check-box.
2. No overflow support. I.E scroll bar or multi-line.
3. Fixed Width. Ideally a movable separator will allow dynamic resizing.
Hope this helps implementing this much awaited feature.
Thanks for your work.