Reduce size of $PGDATA for "demo cdrom"?

Hi all -
We've got a product built on FreeBSD and PostgreSQL 7.4.2 that
I've had to fit onto an installable CDROM tradeshows and customer demos.
This is the only way I've found to ensure an easy to re-install option
for the non-technical folks at the tradeshows should they corrupt the box
itself. This part all works fine.

However, I've only got 700mb to work with and the bootable CDROM takes a
chunk of that as does the rest of our app.

Doing a pg_dumpall of the database results in a 369Kb file.

However, $PGDATA is around 60mb.

root(at)tradeshow:/local/pgsql/data% du -hcs base/* pg_xlog/*
4.4M base/1
4.4M base/17141
4.4M base/17144
4.4M base/17145
6.6M base/17146
5.4M base/17147
16M pg_xlog/0000000000000006
16M pg_xlog/0000000000000007
62M total

My question is what's the best way to trim that down? I realize I could
remove it completely and have my install script do an initdb, etc, but if
there's anyway to keep the installation intact to begin with I'd prefer
that.

Is there any other way to trim the size of those files? Maybe dump
everything out, "clean up", then restore it. Then immediately burn things
to CD? Or if there are postgresql.conf options I can set to not keep WAL
logs, etc around that would work too since this is just for tradeshows...

Thanks all!

-philip