Gotta love the web..
Just a quick update: Andy Lester read the original Combining ack-grep and xargs post and was so kind to point out a much better way to ignore unwanted files while searching i.e.
$ ack-grep --python --ignore-dir=tests/ -C 3 -w 'Message\('
as opposed to
$ find . -name \*.py | grep -v tests/ | xargs ack-grep -C 3 -w 'Message\('
Tags: ack-grep