Rona Lachat: They could order them for you. They are very limited in production.and may be out of stock.
Most have already been bought up by coin collectors. Give this place a try. They make them.
Sure. Many, if not most banks likely have them. One sees them in circulation from time to time.
The vast majority half dollars that were in circulation at some point in time have been returned to the central bank. A bank most likely won't waste their time with hunting some down.