Duster Rear Window Louvers
I know people who used to make resin molds for model kits. It was /not/ that expensive for them. Why couldn't we just use that? Surely fiberglass resin is strong enough, or even the aluminum. That way, it's more man-hours than actual cost.
I /really/ wish I had the startup cash, cause I would be all over this. As far as I've seen/understand, it's not hard. I had the guy explain the process to me before.
Personally, I think sheet metal ones would look just fine as well.