According to web analyst Michael Patcher from Wedbush 5 different Rockstar Studios are currently working on their own discrete projects.
We get this info from Michael Patcher who released this great piece of info to investors recapping his experience of this years E3. Patcher reportedly said that at least one of these Rockstar projects would have a certain launch by March 2013 which is the end of Take Two’s Fiscal year.
Patcher believes that the game due this fiscal year will be none other than the recently announced Grand Theft Auto V, he also said that a pre-holiday release is less likely however he said retailers would likely be told of the game’s launch 3-4 month is advance which suggests a GTA release date reveal is almost certain by November.
one is obviously GTA V...
I'm guessing the other four are...
Red Dead Revenge