Whatever this 'super-secret' game is.., here's a run-down of the SCEJ and affiliated teams that have not announced anything yet (that I can think of)...
Team 'Ape Escape' - there was one ape escape RPG on PSP when? Early this year? Wasn't well received, but it should be time for a new project.
Team 'Ico' - called the 'olympic team'. But 4 years isn't up yet since SoTC's release. They can announce their new project, of course...
Team 'locoroco' - well they already announced the sequel. But at the end of the released trailer there's a few seconds of high-res "cocoreccho!" at the end. Maybe a hint to a sequel?
Media Vision - They are independent, but do develop Wild Arms published by Sony. X-Fire was released on the PSP last year ~July I think. Should be time for something new - but not necessary Sony, of course.
Game Republic - their games range between "meh" to "OK/good". Again they are independent, but do have a history of developing Sony-published games. Of course no one expects the "super-secret-awesome game" to come from them...
Oh yeah, 50% chance this will be another disappointmenton.