Totally agree! and so does the article... See point #5, the second bullet.
In the past I've given candidates projects that we've come up with together. Check out the ones mentioned in the article... fairly straightforward Rails plugins. One of the was particularly successful, and included in the Advanced Rails Recipe book.
You should write that, then.
Hopefully the point remains: review as much code as you can, and don't be shy of asking them to demonstrate their skillz.