I just saw this: http://withrobot.com/en/camera/ocam-1cgn-u-t/
It is a USB camera that has a global shutter and can take an external trigger. That means, not only no rolling shutter distortion, but you can synchronize 2 cameras for stereo vision processing. All for $160, which is much less than other triggered cameras I have seen.
Has anyone used the cameras from WithRobot (also sold on the ODROID site)? Anyone played with stereo?