The puzzle of Level-5's unannounced TGS games may be partly solved already. News out of Famitsu (via Siliconera) reveals a new Professor Layton game for iOS and Android. Professor Layton and the Century of the Seven Phantom Thieves puts players in the role not of the top-hatted archaeologist, but a user-created avatar who searches for information on thieves in London.
Players also gain an unspecified advantage for working with others to catch thieves. More importantly, they gain a little Luke puppet for their avatars for registering early. Information is currently scarce for this game, so it's unclear if this social game has a traditional puzzle element.