Thanks to AngrySparrow for finding Devil Woman Flags.
Devil Woman (her real name is Barbara) has machines for embroidering designs on nylon flags. These flags are tough; several of her designs are specifically made for flying from a car window!
Barbara has set up links for ordering two types of flags for HammockForums.net users. Pictured first is a Flag, then a Patch:
The Flag is simply two Patches sewn together.
Barbara will make a 10"X13.5" single sided PATCH to be sewn onto a hammock or tarp, for $10. Click here to purchase an HF PATCH to be sewn.
Barbara will make a 10"X13.5" two sided FLAG to be flown, for $20. Click here to purchase an HF FLAG to be flown.
I have ordered a sample, which will be delivered in a few days.