I've been working on the Nexista Authn application lately, as well as reviewed the phpass class by Solar at the Openwall project. While the phpass is a great tool, I'm going to keep Nexista Authn simple and light. Conversely, I'm also planning to create an example of how to use the PEAR Auth module with Nexista. I don't think it will be very difficult, and the PEAR Auth module is incredibly flexible.