CNET Asia suggests freezing your DSLR to get better results from the CMOS sensor, or CCD sensor in this case. The overheating issues with CMOS sensors are fairly common knowledge. Anyone that has shot with the Canon 7D for extended periods of time will attest to this. The red blinking thermometer is a party I like to avoid.
An anonymous poster on 4chan put up this image shot at ISO 3200. The bottom still image is from a cold CCD; the top is at room temp.
This brings up the overheating issue. Footage shot with the blinking thermometer could be degraded, compared to footage shot prior to overheating. This is something I hope Canon will address in a future firmware update. Otherwise, keep the dry ice close by.