There are a few places that can make you good quality call sign patches with various combinations of letters and numbers. If you want something a bit more custom and intricate, your options are pretty slim. Perroz Designs is one of the few manufacturers I know willing to take on such work and they do it very well. They recently did some excellent work for my friends at Blue Force Gear that is worth showing off.
The custom patches that they created will be seen at SHOT Show, so they have to look good. The patches feature IR reflective or 3M SOLAS visibile light reflective backings with Wolf Grey nylon covering.