According to an article, the new project by BioShock creator Ken Levine will be an original IP

In a piece about the current boardroom moving and shaking at publisher Take-Two, the LA Times describes Levine, currently President at Irrational Games (formerly 2K Boston), as being "freed from working on the [BioShock] sequel in order to produce an original title that could become another franchise."

Reports had speculated that the project could be an X-Com or System Shock sequel, but if the LAT is accurate, then we'll have to wait until Irrational formally unveils its project to find out what it is. Levine implied that would be after GDC, but 2K Europe told us there are currently no plans to unveil the game. Hopefully that will change before E3...