First some background. About a week and a half ago, a picture of Full Metal Panic Sigma volume 15 was posted to twitpic with the comment "The new volume arrived, but I don't think the news on the band is supposed to be out yet, so it's mosaiced." The internet did what it does best, and assumed the big announcement was the 4th season.
Today, a picture of the band leaked, leaving the internet in disappointment.
The big news? A new Full Metal Panic novel project starting this summer. Called a "Spin out," the new project takes place over 10 years after the main story. Full Metal Panic series creator Shoji Gatoh provided the draft and will be supervising while series illustrator Shiki Douji and series mech designer Kanetake Ebikawa will be returning. The new project will be written by Naoto Ooguro. It is believed that this is the writer's first published work. The band also announces that there are plans to publish a collection of Full Metal Panic short stories around the same time.
The internet asks again: Where is season 4?
Update: The mech designer has posted the key visual art to twitpic.
Update via Moe Ota News Sokuhou
Image ©Kadokawa Shoten