Homepage at http://homepage.mac.com/svc/kpax/.
A very brief assessment of all web frameworks listed in cliki was carried out in September 2010. This assessment comprised: check websites, download source if available, attempt to compile, review documentation.
The review found that, to quote the website, 'Altough KPAX is quite mature and has been in production use for years, the documentation is currently not good enough to support use by the general public.' Not encouraging.