I ended up writing an AppleScript to open the Safari passwords dialog because I got sick of hunting for the proper dialog. If you save it as passwords.command and make it executable it'll open the window right up. But yeah, it's a kludge.

  #!/usr/bin/osascript
  tell application "Safari"
    activate
  end tell
  tell application "System Events"
    keystroke "," using {command down}
    set pass_button to (button "Passwords" of toolbar 1 of window 1 of application process "Safari")
    click pass_button
  end tell