raw is actually relatively simple. Most cameras will have to have the pre-debayer/pre-jpeg readout of the sensor somewhere. As long it isn't completely hidden behind some opaque hardware, find it, write it to a file, there's your raw! This not to make light of work Vitaly and Grand did early in CHDK, getting to the point where you can do that is a big job.
A bit OT, but CHDK raw doesn't necessarily buy you a lot. You get a little more dynamic range, and you can do white balance after the fact, but it's only 10bpp (some newer cameras are 12 bit, but only about 10 bits are significant. wth Canon ?), and the sensors and optics are major factors in quality. It's useful in some specific situations, but raw isn't going give your P&S snaps the same quality you get from a much more expensive camera that has native raw capability.