By icons I was primarily looking at icons for the categories in "file.menu" i.e the main menu.
There aren't any there while the cairo-dock menu does use them.
I found most in "/usr/share/icons/gnome/48x48/categories/".
For the .xpm icons we'd have to find alternative .png icons and name them appropriately for the script to work. Some apps (especially in Games) are so old that they've only got .xpm ones. But then again there aren't that many.
If I do grep xpm in menus_apps I get this:
"/usr/share/pixmaps/a7xpg.xpm"
"/usr/share/games/desmume/glade/DeSmuME.xpm"
"/usr/share/games/desmume/glade/DeSmuME.xpm"
"/usr/share/pixmaps/parsec47.xpm"
"/usr/share/pixmaps/scummvm.xpm"
"/usr/share/pixmaps/torus-trooper.xpm"
"/usr/share/pixmaps/urxvt_48x48.xpm"
"/usr/share/pixmaps/unison-gtk.xpm"
"/usr/share/pixmaps/cin.xpm"
