I think it's easier to write a portable Tcl installer than 
a sh based one (it's easy to end up using flags not supported everywhere or depend on commands that don't exist in some
OS's).  For a Tcl based install we could do it with a 
tclkit
and there are tclkit binaries for pretty much any platform 
I think people are interested in.
Otoh, you can definitely exit on errors with a shell script 
set -e
 does that and you can use the trap command
to catch the error (although I think that is a bash-ism and 
you cant trap ERR with vanilla sh).
I would like to see packages for .debs, .rpms, and ebuilds and any of the half dozen other package managers people use.  
I suspect the best way to get there would be 
to have a place in CVS where we keep the source for building with the various package tools (for example there are a 
set of ebuilds to install all the aolserver stuff + openfts and writing an openacs ebuild would be pretty easy).
Maybe we should create  an openacs-4/etc/installers/DISTRO directory and under that have the source for generating the 
various packages/build scripts.  If we get them working well 
then 
I imagine they will get pulled into more standard distributions.  
Another alternative would be to try harder to become 
the maintainers of aolserver and openacs on various
 standard distributions.  The problem seems 
to be that the people maintaining aolserver for the various 
distributions where it is present are not really very good
at keeping up to date.  I don't know how hard it would be to 
get commit on gentoo and debian for example, and I don't 
follow fedora at all.
Anyway, there are a lot of options; I think getting 
things into standard distributions is important but I don't 
know how it will happen until some people here get commit 
to maintain the necessary packages.