I am now using live-helper's autoconfig with Debian Live SC.

commit 347c832f1bd3c1d54315ab597e7a8e8b6cfc9fd7
Author: Svend Sorensen
Date:   Wed Feb 18 12:25:17 2009 -0800

    Use autoconfig to build config files

 config/binary    |  154 ------------------------------------------------------
 config/bootstrap |   53 -------------------
 config/chroot    |   61 ---------------------
 config/common    |  123 -------------------------------------------
 config/source    |    9 ---
 scripts/config   |    7 +++
 6 files changed, 7 insertions(+), 400 deletions(-)

7 insertions(+), 400 deletions(-). Nice.

There is a good example of a live-helper config using autoconfig here.