pex. It's targeted at developers, allows easy customization, and supports multiple PostgreSQL installations.
Here is how it works:
git clone git://github.com/petere/pex.git cd pex sudo make install
Install some packages:
pex init pex install plproxy pex search hash pex install pghashlib
Multiple PostgreSQL installations:
pex -g /usr/local/pgsql2 install plproxy pex -p 5433 install pghashlib
pex update pex upgrade
It works a bit like Homebrew, except that it doesn't use Ruby or a lot of metaphors. ;-)
Check it out at https://github.com/petere/pex.