multiple identities definetly is an interesting proposition! If it derails too much I'd like to fork it off this thread, though.

Just to be clear: do you mean multiple personas at the same time?

If so: I vagely recall @dominic saying that core sbot already supports this but just needs some more batteries. I'm not sure if this was about publishing or querying. Also I'm unsure if this can be fed into clients from the shell or how much clients need to change their assumptions for this. I think most will assume my user is what ever is in .ssb/secret.

If not, It might be interesting to consider a simple switcher, though. Having a menu in the systray to switch form one persona to the next and having sbot reboot.