Guys, by all means use the LucasArts store contact form (
http://store.lucasarts.com/contactus.xml) to proclaim that you'd like to see Grim Fandango available again so you or a friend can buy it. Companies like LucasArts will only respond to demand, and if there's no perceived demand for it then they won't even think about bringing it back — even if it would take them very little effort to do so.
Even several emails about it on a regular basis would make a difference, as chances are the small team that deals with the emails will notice the repetition. And as far as I'm aware, they're obligated to send out at least a response as long as the question is valid (eg: When is Grim Fandango going to be available again?).