Don't know about their appearance in the annual, but the ASL Digest had an article about personal leaders in volume 6-4. You can find it
here.
I usually use personal leaders when I play SASL. Each campaign company I run has one tied to it, and one 'free range' leader from each nationality for one-off games. I use the regular leader advancement rules in section S17.73 and the personal leader points system for the personal leader.
[update - sorry, just checked the link on that site and realized it doesn't go anywhere. But if you can track down that issue of the Digest, that's where you can find it. In the meantime I'll see if I can translate my copy into a format GS will allow as a message attachment.]