There is already POSIX multiuser support, so you can create non-root users and SSH into them, but unfortunately this is indeed not integrated into the GUI yet.

There is already POSIX multiuser support, so you can create non-root users and SSH into them, but unfortunately this is indeed not integrated into the GUI yet. You can definitely lock the screen, at least, though...? Not sure what you mean by "integration with today's web services." Our WebKit port could still use some more work, but a lot of the modern web is at least functional.