Thank you, Éva! This helped me get a much needed start. I've added in feedback, and some descriptions. Tested in Moodle 2.5 with the Reports add on.
-john
SELECT crs.shortname AS course, asg.name AS assignment, gd.name AS rubric, grc.description, grl.definition, grl.score, fdb.remark, rubm.username AS grader, stu.username AS student, FROM_UNIXTIME(gin.timemodified) AS modified
FROM prefix_course AS crs
JOIN prefix_course_modules AS cm ON crs.id = cm.course
JOIN prefix_assign AS asg ON asg.id = cm.instance
JOIN prefix_context AS c ON cm.id = c.instanceid
JOIN prefix_grading_areas AS ga ON c.id=ga.contextid
JOIN prefix_grading_definitions AS gd ON ga.id = gd.areaid
JOIN prefix_gradingform_rubric_criteria AS grc ON (grc.definitionid = gd.id)
JOIN prefix_gradingform_rubric_levels AS grl ON (grl.criterionid = grc.id)
JOIN prefix_grading_instances AS gin ON gin.definitionid = gd.id
JOIN prefix_assign_grades AS ag ON ag.id = gin.itemid
JOIN prefix_user AS stu ON stu.id = ag.userid
JOIN prefix_user AS rubm ON rubm.id = gin.raterid
JOIN prefix_gradingform_rubric_fillings AS fdb ON (fdb.instanceid = gin.id)
JOIN prefix_gradingform_rubric_fillings AS grf ON (grf.instanceid = gin.id)
AND (grf.criterionid = grc.id) AND (grf.levelid = grl.id)
WHERE crs.id = <course_id> AND gin.status = 1