I have recently installed a new version of CHDK (version 1.3 from today) and gained the ability to write the full sensor data to the DNG file.
What this means exactly (for those who are not up to date on this) is this:
A regular DNG file gives a 4000x3000 image (12.0 megapixel) for the SX130IS.
A full sensor DNG gives a 4080x3048 image *BUT* it has a black frame on all sides, which leaves you with 4032x3024 of usable resolution. (12.192768 megapixels to be exact) or a ~1.6% increase in resolution
Now we have access to those few pixels that were unavailable before (it says 12.1 megapixels on the front of the camera, remember). Note - .jpg images from camera are unchanged @ 4000x3000.
This will probably not mean much to most people who wont even bother with it, especially since the cropping is an extra step in your workflow. Only pixel peepers will be able to notice. However, I am not most people and welcome every single extra bit of quality out of the sensor
So now at all zoom settings you will have a few extra pixels on each side that are not in the jpg. If you happened to be missing the tiniest (like 16 pixels from top or 12 pixels from side) bit of your image from the frame, you might just get it back by looking in the raw.
All in all, I'm happy with it