There are some prefs availble in galeon that are not directly avaible in
the UI, for one reason or another. Thanks to GConf it's easy to set them
from the commandline using gconftool. See the Gconf docs for more info 
(gconftool --help may be enough for you). You could get this info also
from the schema file (galeon.schema), but I've put here only the options
that are not avaible from the UI.

   The prefs that are currently not avaible in the UI are:

User agent: 
/apps/galeon/Advanced/Network/user_agent (string)
        use "default" for the default galeon string

Number of items to show in the autocompletion list when it's shown 
automatically:
/apps/galeon/Browsing/History/completion_max_short (int)

Show tooltips for bookmarks menus:
/apps/galeon/Browsing/Bookmarks/bm_tooltips (int, 1 to show)

Autobookmarks item title max length:
/apps/galeon/Browsing/Bookmarks/autobookmarks_shorten (int)

Number of autobookmarks to generate in each folder:
/apps/galeon/Browsing/Bookmarks/autobookmarks_count (int)

Title of galeon windows:
/apps/galeon/UI/Windows/windows_title (string)
%s is substituted with the current URL.

Default width for smart bookmarks in the toolbars:
/apps/galeon/Browsing/Bookmarks/smart_bm_entry_width (int)

Show SBM arrow buttons:
/apps/galeon/Browsing/Bookmarks/smartbookmarks_hide_arrows (bool)
When TRUE, the arrow buttons in a SBM will no longer be shown

Mouse wheel
/apps/galeon/UI/Mouse/wheel_nokey_action (int)
/apps/galeon/UI/Mouse/wheel_shift_action (int)
/apps/galeon/UI/Mouse/wheel_ctrl_action (int)
/apps/galeon/UI/Mouse/wheel_alt_action (int)
Wheel actions. Possible values are 0 (Scroll by
        one step), 1 (Scroll by one page), 2 (Move in the browsing history), 3
        (Zoom)

/apps/galeon/UI/Mouse/wheel_nokey_default_step (bool)
/apps/galeon/UI/Mouse/wheel_ctrl_default_step (bool)
/apps/galeon/UI/Mouse/wheel_alt_default_step (bool)
/apps/galeon/UI/Mouse/wheel_shift_default_step (bool)
Use system default step

/apps/galeon/UI/Mouse/wheel_nokey_step (int)
/apps/galeon/UI/Mouse/wheel_ctrl_step (int)
/apps/galeon/UI/Mouse/wheel_alt_step (int)
/apps/galeon/UI/Mouse/wheel_shift_step (int)
Scroll step in lines

History lists on rightclicking on the context menu navigation items
/apps/galeon/UI/Mouse/history_popup (bool)

Favicons in tabs
/apps/galeon/UI/Tabs/favicons_in_tabs (int)
0: no favicons in tabs
1: favicons in tabs
2: only favicons in tabs when there's one

Automatically fetching of host favicons
/apps/galeon/Browsing/General/host_favicons (bool)
Automatically download host/favicon.ico

Minimum numbre of bookmarks to ask confirmation when deleting. If it's -1, it 
will never ask for confirmation.
/apps/galeon/Browsing/Bookmarks/remove_confirmation_min (int)
This is not totally hidden, but it's not avaible from the prefs window.

Show titles in the autocompletion alternatives window.
/apps/galeon/Browsing/History/completion_show_titles (bool)

Make the autocompletion alternatives window as large as possible.
/apps/galeon/Browsing/History/completion_huge (bool)