Hello & welcome, Wes !
1) I few of my RAW photos do not have corresponding JPG files. Why would this happen?
Since now we can't disable saving JPG files with CHDK, so that's odd...
Maybe they are stored in an other folder, 000CANON or so ?
Is there a pattern on the missing files, e.g. each n-th file, last file in a Canon folder etc. ?
Is the SD card ok, maybe the file system has some problems ? (you can run a fs-check, e.g. with Scandisk under Windows - after you've copied all the images to your harddisc, of course !)
2) I found that when I go into the settings and enable bracketing, take a few photos, power off the camera and power it back on the settings are not remembered. This means that every time I power cycle the camera I have to reset the bracketing settings -- very much a PITA. Is there a way to persists these settings across power cycles?
This is the default setting ("Clear override/bracketing settings on start"), you can change it, just disable this settings...
3) I am currently using an old A540 and would like to upgrade to a newer Powershot that will provide better quality photos. I don't want to spend a ton of money so probably won't get the latest and greatest, but something with much better quality and a good value. What would you all recommend?
Hmm - "better quality" doesn't mean "more mega pixels", the quality (e.g. noise) of newer cameras is not really much better, the post-processing of the images is better...
Some -maybe helpful- links:
*
CHDK wikia: supported cameras*
Cameras] CHDK wikia: all camera pages (you'll find review links on most of this camera pages, also you see whether it is supported by CHDK)
