separating PG binaries into a ro mounted partition

Hi,
~
I would like to separate all PG binaries from the created data for
tables, indexes (which could be written and updated to) and also from
the log files created by PG. Idealy I would like to be able to reset
those directories at run-time through environment variables and even
run PG from a CD-ROM
~
So I will need to include those a-la {$DATA_DIR} in conf files and
previously set them in an initial script
~
I know I will have to install PG from source, but I guess there is a
lot more I don't know about the installation procedures found in the
/postgresql-8.2.5/INSTALL notes, my ./configure stat should be like
this:
~

PG_INSTALL_DIR=<>
RM_DIR=<>

./configure
--prefix=$PG_INSTALL_DIR
--without-readline
--without-docdir
--mandir=$RM_DIR

rm $RM_DIR
~
I am planning to use the read-only mount feature and the append-only
attributes of the ext3 file system under Linux
~
Which other conf files will I have to tinker with?
~
Are there any best practices using these ideas for the installation of PG?
~
Thanks
lbrtchx