There are actually plenty of movies that have 6-letter titles. There's "Top Hat," which starred Fred Astaire, "Desire" starring Gary Cooper, "Munich" starring Eric Bana, "Legion" starring Paul Bettany, and "Casino" starring Robert Deniro.
You can go to Sporcle.com to play a fun online game focusing on 6-letter movie titles!
Among new movie releases is the movie "The Host." It stars Saoirse Ronan, and centers around a young girl named "Melanie" who is played by Saoirse. The movie is based on a novel written by the "Twilight" series writer, Stephenie Meyers.
However if you prefer new 6-letter-title movie releases look for Detour, Mental, and Renoir, all just released to theaters.