Just saw a report that the shortage is so bad that buyers are switching to more obscure calibers such as 25ACP, 32ACP, 32HR, and 45Colt. Even the long forgotten cowboy calibers such as 44-40, 32-40, 32-20, 38SW, 32SW, and 32Colt, are all flying off the shelves these days. People are buying guns for these secondary calibers because the ammo is available (although costly), or they have grandpa's old antiques firearms sitting around and are the only firearms that they can still find ammo for.
I've never dealt with specialty antique caliber ammo suppliers, but I'm quite sure that they are doing big business these days.