This board never really left (though it was painfully slow for a while there).
Anyway, your plan sounds solid, but you don't really need any special grills for 6x9's. If it were me, I'd get some of that "honeycomb" mesh the tuners are using (or something similar) and just sandwich it in underneath the fabric. You could get actual speaker grill material, but I'd probably just go to your local craft store and find some tweed kinda stuff. Another option would be burlap. You probably won't find it in black, but it does take paint rather well.
If you want "real" stuff, you might try
http://www.Parts-Express.com. Their website seems to be having some issues right now, but when I did business with them a few years ago they were great.
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Used to own:
'82 Dodge D150
Erson 270 Cam, O/S valves, mild port work, ~9.5:1 compression
Currently fighting with an '85 VW Cabriolet
My other passion