The main question for me is how to make the bracketed pictures. The rest can be done on the desktop. I have come to the conclusion that a little C is neccecary in order to do this.

I compiled a quick and dirty script which uses this C utility and takes a -2, 0, +2 sequence with the current settings in focus and exposure.

to run it

1) Place the files contained in the attached file in a non vfat folder eg., ~.
2) Compose and take a picture in with the default camera application.
3) Close camera application without moving the camera too much.
4) Run photo_bracketing.sh from the command line. Wait.

the three files will be called rawHDRtest0.png rawHDRtest1.png and rawHDRtest2.png