To encourage HN users to ship code, allow them to display an icon next to their user name once they have shipped their project. This would work on the honor system. To make the implementation simple, users can self-manage the icon. Perhaps a "ship" icon could be displayed that linked to the product if applicable.
This will help create a culture of "shipping" through a shame/pride/credibility/game achievement effect, as well as help users keep the HN addiction in check.