Who in their right mind wgets and builds software on a production machine...?

I actually do this with one piece of software, and that is PostgreSQL. I know it in and out, it's easy to upgrade via source, and I prefer to put the database in a bundled location e.g. /data/postgres or /home/postgres... instead of /var/lib/postgresql/9.1/main, /etc/postgresql/9.1 et cetera.

Why not just build your own packages? fpm[1] is very simple to use.

[1] https://github.com/jordansissel/fpm