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 184.108.40.206 to 220.127.116.11, and you...HF10/100 Firmware Analysis
“Canon has released an update to version 18.104.22.168. Where and how to get the firmware and a serial...HV30 Firmware Analysis
“This HDV camcorder was released in January 2007, and has become a very popular tool for indie...HV20
“HD camcorder based on the HV20, the HV30 offers some physical body improvements as well as a new...HV30