Tying "bands" on the head is not difficult. Essentially, it is just tying in a different color thread in the same way that you start your thread on a hook shank except it is done atop an already tied/formed head. A turn or so and a whip finish is all it takes. It can be done with fine oval or flat tinsel too and I often do this. The tricky part is doing it neatly and hiding (burying) the thread ends. If the taper of your head is extreme, the thread will have a tendency to slip toward the narrow end.
Carrie Stevens' signature on her streamers was the band of color. Most often it was orange. On the Casablanca, Victory, and General MacArthur (and maybe one or two others) the bands were red, white, and blue. Whenever I tie her patterns, I like to incorporate the band(s) as a tribute to her and her unique flies.