Some of this has been discussed before somewhere, but all I could find in feature requests was one for an IS on/off shortcut key.
As we know, IS (image stabilizer) should not be used for long exposures on a tripod, because it may cause spurious sensor motion, resulting in blur.
Now, it would be neat if CHDK had an option to temporarily disable IS whenever shutter speed is slower than a user specified value (default could be >1 second or whatever is the slowest Tv autoexposure will ever give).
Even neater would be to disable IS -- no matter which shutter speed -- when the IS sensors reveal that the camera hasn't been significantly moved for a second or two (i.e. "tripod detection"), and re-enable it immediately when camera motion is detected. This might actually cut power consumption a little bit as well.