qstat XML schema documentation
Grid Engine 6.x distributions include a "util/resources/schemas/qstat/" directory that currently contains the following files:
- qstat.xsd
- message.xsd
- detailed_job_info.xsd
These are about the best resources one can currently obtain when delving deep into SGE's XML output behavior. They are, however, a bit cryptic to read. Passing the .xsd files through an XML Schema Documentation Generator has resulted in some more human readable output. The translated files can be found here:

XML Feeds