The Text Encoding Initiative Guidelines provide generic but detailed recommendations for the mark-up of electronic documents, in particular texts from the literary and linguistic domains. The TEI guidelines, converted to XML in 2001, are maintained in a high-level markup which mixes elements combination and content model rules with text documentation. A project to convert this to use RelaxNG internally was described at XML Europe 2002. Because the TEI is modular and extensible, it is accompanied by a web application which assists the user to define a subset and/or extension of the schema and creates an ad hoc DTD. This paper describes a new version of the program, which will enable users to generate DTDs, RelaxNG schemas, and W3C schemas on demand according to their specification, along with instance documentation.