After following steps 3 and 6 from http://ubuntuforums.org/showthread.php?t=690620 I've got grim fandango working on my macbook pro. The key was to use the launcher here: http://www.grimfandango.net/?page=launcher
Additionally, the game only works in "windowed" mode as selected in the launcher -- full screen gives me a corrupt display. Unfortunately, windowed mode runs in a fixed window in the upper-left corner of my desktop and won't move, but it's still playable (especially using os x's zoom for a full-screen effect).