Two lead developers who worked on Grand Theft Auto titles have left Rockstar Leeds to start up iPhone app developer Double 11, reports Develop.  The new studio is headed by Lee Hutchinson, former Rockstar lead engineer who worked on the iPhone version of GTA: Chinatown Wars.   Develop says that Hutchinson is soon being joined by Matt Sphepcar, Rockstar lead programmer on Grand Theft Auto titles including GTA IV.   Hutchinson said the departure from Rockstar was very, very amicable, adding that the move is part of a trend he described as developers who are sick of huge all encompassing next-gen projects and want to get back to grass-roots bedroom coding.   Develop points to another recent move in the same vein, with Lionhead Studios lead designer Dene Carter forming iPhone studio Fluttermind.  The news outlet tags their report with a link to a site survey asking whether large-scale game development has peaked.  Read more and access the survey at Develop.