Users of Canon's camcorders have asked for tools like chdk. There is some work happening on various models.
“The HF10/HF100 is an AVCHD camcorder (saves footage to a SD card in AVCHD format, compared to...HF10/HF100
“There's an official firmware update available which updates version 220.127.116.11 to 18.104.22.168, and you...HF10/100 Firmware Analysis
“Is there yet or going to be a version of CHDK for the Canon FS100? It would make my day if there...CHDK for Canon FS100
“This HDV camcorder was released in January 2007, and has become a very popular tool for indie...HV20
“Canon has released an update to version 22.214.171.124. Where and how to get the firmware and a serial...HV30 Firmware Analysis