Patlac--Xml2cpp is a totally customizable code generator that generates classes (c++ for now) automatically from a xsd schema. Classes are described in google-ctemplate files and a xml options file allow precise definition of projects.
Caudium WebServer is a single process multi-threaded webserver. It has a built-in pre-processing language and includes an easy to use web-based configuration interface.
Schema validation with simple dom php classes, that will check the xsd file before the xml based forms will accept any submit. The ajax wrapper should work with widgets to show any validation error to the form user.