http://www.sil.org/sgml/sgmlnew.html
and details are in the main XML document:
http://www.sil.org/sgml/xml.html#xml-omg
This seems like a pretty significant initiative, unless
one does not care about object/component modeling, (STEP)
schemas, and the unification of several important
industry standards,including XML. The two most relevant
documents are available in PDF and Postscript.
Enjoy.
-rcc
PS. Don't write to say that the XML document is "too
long" - I'm about to start fixing it... sorry.