It's been quite awhile but the cover letter paraphrased-

I have X experience with Y but that doesn't really tell you what I'm capable of or what my work is like. Let's walk through developing a simple module for Y...

• Terse problem space discussion.
• List of concerns like system/coupling v unit testing.
• Simple/direct way to get it into Y with terse code snippet.
• Distribution/RCS concerns, pros of using standard CPAN style dists even at work.
• Link to newly uploaded CPAN package!
• Thank you for this opportunity!

And since I sent the letter just a few hours after the job posting, it was, I hoped, obvious I could 1) perform quickly, 2) communicate, 3) write functional, testable code to community standards.

It was fun. At the time I was actually really nervous and thinking it was a mistake; arrogant, a bundle of work for free on spec, too outside the box... I feel like I'm a very middle of the road hacker so it's hard for me to promote myself. Not that I don't do a good job, I definitely endeavor to. The thing about Perl is, the better I know it the more I feel like it's just so damn deep I can't make definitive statements like: I'm a Perl guru. So, I don't and I end up sounding like a clinker if I'm not careful. I try to talk code and how fun/productive Perl is instead of "me."

Job hunting is, I've mentioned here before, a lot like dating. A positive attitude, confidence, love of Perl are very attractive to Perl employers.