Rated 4 out of 5 stars
This is good.
However, I want to display tab bar to the right of the folder pane and display always folder pane, if possible.
Not what this extension is ment to do
In theory the behaviour you describe is possible. However, it has a very high risk of breaking something, as it would need to move MANY things around:
1. the toolbar above the tabbar, just like rise of the tools.
2. the tabbar into a new container, which also includes the content switched with the tab
3. the folder pane into the parent of this new container
Even this add-on did not get a full review here, with a smaller risk of breaking something. So I personally don't think this is possible with keeping Thunderbird staying stable, as there are various add-on combinations possible.
However, a dirty implementation without cleanuping when disabling, etc. should be easy to do, if you really want this write me an eMail - but I won't try to submit that as public add-on.