The original creator of Full Metal Panic!, Shoji Gatoh, tweeted his plans for 2012. After noting that the latest volume of Full Metal Panic! Another will be out "surprisingly soon," he added that he's doing series composition on the school mystery anime, Hyouka and gave some details about his upcoming "slapstick drama" novel.
Set at an underwhelming amusement park in the suburbs of Tokyo, Amagi Brilliant Park (working title) features a protagonist with lots of problems. Gotoh's best guess at the timeframe for a larger announcement is this summer.
He's also looking to continue the science-fiction, crime light novel series, Koppukurafuto: Dragnet Mirage, but seems unsure whether that will happen or not.
Finally he said (roughly), "Besides that, I also have plans for this and that in 2013 and beyond that I can't say anything about yet," noting specifically, "By the way, plans I can't talk about include a few things that have a 'long-awaited' feeling. It's all way down the road, though."