Raw access to CMOS image sensor?
You might want to read about the Kepler spacecraft's CCD readout system.  Monitoring thousands of stars at a time continuously, with 42 CCD chips, is just too much data.  It doesn't take conventional 2D images but reads out only the CCD cells in areas of interest.  Sounds sort of like what you're asking about.

Basic info
http://kepler.nasa.gov/Mission/QuickGuide/MissionDesign/PhotometerAndSpacecraft/  

More detailed technical info
http://iopscience.iop.org/2041-8205/713/2/L87/fulltext/apjl_713_2_87.text.html

Plenty more is available online, in particular from NASA Ames and the SETI Institute.