I have been working on a new niche directory website. The code for the directory will probably be publicly available in the near future for release. The script would feature an admin area approving/denying/editing links in the directory and handling payments for featured links. The script should be free and open source and very simple to install and use with pre-existing templates.
The website is still in testing and the working site is almost completed. All it needs is links to be added to the directory and to be submitted to the web.