if you want to hack a bit, you can just use 'enfuse' - the command line utility bracketeer is based on (and where all the real magic happens anyway).

combine it with the iphoto plugin from below:
http://www.n8gray.org/code/scriptexport/

create a few simple shell scripts, and then the whole process is automated. you just select the multiple exposures in iphoto, run "export.." and the final image is created on your desktop (or wherever)

here are the 3 scripts i created for scriptexport:

enfuse-pre.sh:

#!/bin/sh
# create a working dir (make sure it's empty first)
rm -rf ~/Desktop/enfuse-working &1>/dev/null &2>&1
mkdir ~/Desktop/enfuse-working

enfuse-per.sh:

#!/bin/sh
cp "$iPImagePath" ~/Desktop/enfuse-working

enfuse-post.sh:

#!/bin/sh
#process the images, putting a timestamp on output file
/path_to_enfuse/enfuse -o /path_to_put-result/enfused-`date "+%Y-%m-%d_%H:%M:%S"`.jpg ~/Desktop/enfuse-working/*

#remove the working files
rm -r ~/Desktop/enfuse-working