Thanks for the ideas-- I think I will definitely hunt around for a laser that will do the trick. Offhand I don't know anyone with the appropriate machine. I've used a great online resource for other parts but they won't do metal that thin.

I will experiment with cutting it with a knife. Scoring against a straightedge has always been a somewhat error-prone process for me, I'm not sure if I can achieve the precision desired for this.

When cutting with a band saw how do you support the work? I'm imagining the thin metal bouncing up and down as the blade passes producing a rough cut, at least that's been my experience sawing thin sheet metal, hence my idea of sandwiching it in plywood for cutting.