There has been some discussion on the METS list of a Relax NG version
of the schema. Using the Sun RelaxNG Converter, I did a conversion of
METS 1.6, with clean up by hand, and posted it to the METS wiki .
I have now done a related conversion of MODS 3.2, using the same
method, and have put this as well on the METS wiki. I have tested this
against all the sample MODS on the MODS web site (after changing the
version attribute to 3.2), and all of them conform to the grammar
according to the Sun Multi Schema Validator.
Of course, these schemas are not normative and are not endorsed by
anybody, but I would appreciate comments, suggestions and corrections.