About the blurred image, the rotational acceleration is no good when the diaphragm camera is open, so is better put the camera in the center of gravity (very lovely point for Gluon module, batteries etc, It´s a party point, ). As general, shutter speed works fine between 1/500s and 1/1000s.
There are other good cameras you can buy from second hand like Sony NEX-5, Olympus Pen, Panasonic GF1... and aren't Cannon (so no CHDK). All have fixed shutter speed an a medium sensor size but more heavy. For any camera you choose I think is good to store picture at RAW format. You have time to lose quality later. There are shops (no publicity) who sell ready breakboard with microcontroller to read PWM (from Gluonpilot) and switch on IR LED or optocoupler (I don´t tested today). Optocoupler is a good option to handle your camera shutter board if it hasn´t IR remote controller.
I will remove publicity if it's not allowed ¿?. This is the switch for PPM or PWM.
http://www.rc-flysoft.com/pages/switchidx_e.htm (no tested still)