If you are programming sort of person, look at http://maemo.gitorious.org/maemo-mul...n/gst-camera.c example. In handle_element_message() it shows how to handle RAW data buffer coming from v4l2camsrc, and on_chkbtnRawMsg_toggled() shows how to trigger v4l2camsrc to produce that RAW buffer.

RAW data is 10-bit BAYER (two bytes per element) if I'm not mistaken.