Need a source for .080 reflective brown alum (3" x 36")

How many ??

 

Grimco sells aluminum with reflective sheeting pre-installed.
contact whomever you get your substrate from.

or get the aluminum blanks and apply the reflective as needed

 

if your suppliers are unable to cut the material for you, really odd if they can't.
Try calling a local machinist / CNC operator and have them cut multiple sheets of material, you then apply graphics as needed

 

harbor sales in maryland can cut the 080, you'd have to apply the reflective yourself

 

I think you answered your own question...... just get a heavy person on that machine and keep the cost in-house.