There is officially a Shippuden Movie 4 already...and it's on show in Japan already too..here's the link...

Naruto Island - Sakura, Sasuke, Naruto Episodes, Movies, Comics, Games

The date of release of Movie 4 in Japan was 8th August 07..also a 14 seconds trailer and it's quite mysterious since it looks like Naruto died..although nothing can be explained since we haven't watch yet xD