Here's a cool item I purchased for my US Army kilt. It's a repro of a Civil War era army officer's hat badge. It's black and red wool with gold and silver thread embroidery, and about 3" wide. You can custom order a regimental number (I was an officer in the 2nd BN, 35th Field Arty).



You can buy such a badge here:

http://fcsutler.com/fcinsigniaemb.asp