> XML Schema is incredibly mature and robust (and an ENORMOUS pain in the butt to write). The way I do it is to define classes in C# and annotate with attribut

> XML Schema is incredibly mature and robust (and an ENORMOUS pain in the butt to write). The way I do it is to define classes in C# and annotate with attributes (either DataContract and/or System.Xml.Serialization) and then export the schema as a set of XSD documents with the accompanying catalog file.