Retroreflective American Flags are easy to find as well.

http://www.whitehorsepress.com/product_info.php?cPath=1_14&products_id=3936

The 2.9 by 1.5 inch flag exceeds 4 sq in.

Among the multitude of challenges life offers,
I think I'd put this fairly trivial one on to the "Do Not Whine" list.