I used one of the metal mesh trash cans.
I routed a recess in the speaker panel and tacked the mesh down with staples:

Then I "painted" the mesh with 2 part epoxy, bringing it to s smooth surface level with the surrounding wood:

After a final touch up with Bondo to completely smooth it out:

I painted the panel black:

And then covered it with black grill cloth:

This is what you see looking up at the finished speaker panel:

It's extremely acoustically transparent, and protects the speaker cones very well.
Way more detail is on the construction web site:
http://www.ogredog.com/mame_construction_home.htm...staring around day 13.