@Beta
A good indication of whether or not the remote script is working is to check the camera features page
http://chdk.wikia.com/wiki/CameraFeaturesPay particular attention to the Min USB Volts column, if a voltage is listed then that should mean someone has gotten a USB Remote to work with that camera.
There are other cameras that have HD and work with CHDK, for example I have an SD780IS (IXUS100) and can confirm the USB remote working in SDM and the German version of CHDK (the "normal version" will hopefully be corrected soon).
As long as you know there is a CHDK version available for the camera you buy you can always get it, try it out, and take it back if its not compatible.