LEGO announced that they will release sets in the Lord of the Rings theme in 2012! This will certainly include interesting Minifigures. Given that LEGO produced already Dwarfs, Elves, Orks, Wizards and all sort of other creatures, it does seem almost like low hanging fruits to design sets and figures for Lord of the Rings. Fans already produced many scenes from the movies, including The Last March of the Ents which includes an enormous Isengard. The only figure that might be a design challenge could be Gollum. I also wonder how Frodo is going to put on the ring, since Minfigures do not have any fingers.
