The devrel address has been pretty responsive im my experience. You usually get an answer after a week or so, and if you found something real the fix will show up two official driver releases later.
I suppose you can get much faster turnaround (replies, beta drivers) if you are of some demonstrable importance in the grander scheme of things.
Every bug report should have a simple and well documented test case, including full source. Using the glut library as a foundation is a good idea because it lets the test case be more focused on GL, and less on OS glue.