[comex]

Well, I quickly went through all of the default preference panes and here are all the Advanced buttons:

    Security & Privacy
    (Displays - Calibrate has an "expert mode")
    Mail, Contacts & Calendars - for manual mail accounts
    Network - big advanced section
    Bluetooth
    (Zoom in Accessibility has "More Options...")

So there's a few of them, but I wouldn't say lots.