What's about saving, working with kind of workspace or grouped tabs, collapsing if not used and not being affected by a simple control-tab?
So, grouped tabs are saved as workspaces, collapse automatically on leaving, protectable with a password for re-entering.
Wouldn't that fit your, Olli's, demands?
I would use this feature to group version dependent lists and to seperate those versions and administrative lists in the UI.
Best regards,
Martin