From Anime News Network:
Re-imagines lead characters from Full Metal Panic and Fullmetal Alchemist as main characters from Metal Slug
One week ago at Tokyo Anime Fair, a secret meeting was held between executives at SNK Playmore and editors at Square Enix's and Fujimi Shobo's manga divisions. The end result was a manga spin-off of two of Japan's hottest properties mixed with SNK Playmore's incredibly-popular 2D shooter. "We are all very excited about this new joint venture", said SNK Playmore President Soichiro Hosoya. "Many of our programmers, artists and marketing staff are huge fans of Fullmetal Alchemist and Full Metal Slug, so we felt the time was right to launch (Full Metal Slug)."
Writing duties will be split between Full Metal Panic creator Shoji Gatou and Fullmetal Alchemist writer and artist Hiromu Arakawa. "I'm very much looking forward to undertaking this new and interesting challenge", said Gatou via e-mail. Arakawa could not be reached for comment due to her busy schedule, but her editor said that she "can't wait to work alongside such a talented writer". Artistic duties will be handled by newcomer Yusuke Iwamura.
The first chapter of the Full Metal Slug manga is slated to debut in Comic Gun-Gun Kuro, Square Enix's and Fujimi Shobo's new joint manga anthology, "this fall", according to sources close to the project. Other titles slated to appear include Kayo Haga's "Hop! Step! Jump Star", Sho Akizkui's "King Of Fighters EX Saga", Nanami Takai's "Arcana Heart: Ultra", and Misao Akiyama's "Good Taste" cooking manga.
Update 1:
An anonymous source on 2ch has leaked early promotional art for Full Metal Slug:
Special thanks to flavobar for the update.