Most CHDK cameras only buffer a few shots, and there isn't readily available RAM to buffer more. If you did find enough RAM
, it should be relatively straightforward to re-purpose the remote shoot code to put jpegs in a circular buffer +/- cameras that have trouble with remote shoot in continuous mode.
For RAW, there really isn't physically enough RAM for many shots on most cameras. I have been thinking about a burst mode for cameras with multiple raw buffers (especially digic 6 which have 3 in some modes), so you could shoot 2-3 shots and then save them all at the end. If this were done (it's not clear it's possible, the buffers might get trashed by the native firmware) extending it to only save the last 2-3 images in a burst should be straightforward.