I have ordered a Qoute for 3½ x 7 inches patches with "Pentax *ist D" White letters on a black background, the star being red, of course. I guess it can be cut in two, in order to loose the "*ist D" part, if necessary. It's probably going to be too expensive (like 150 USD for 100 patches).
I guess I could ask a local store selling Bernina sewing machines - they might be able to do this for less, I believe. http://www.flickr.com/photos/bladt/48566139/ We'll see. Jens