Looks like I have a reproducible method to dump the a2000is GM1.00C.
The dump I got can be downloaded from here: PowerShot_A2000IS_GM1.00C.zip - 1.75MB
I haven't stripped the initial zeros, the first nonzero bytes start at B9A00.
My version of udumper is attached to this post. I basically use the udumper version by exander. Once compiled the bootdisk.bin I append 20k of zeroes and then I apply dancingbits. I use cardtricks and a 32M SD card.
The debug led never turns off, this suggests that the call to the write function never returns...however it seems that the dump is created successfully.
Right now I have not enough knowledge to check if the dump looks ok or not, hope some more skilled developers could check it