Mike, Antique Diver's barn is home to a lot of strange and hard to find items. Here's a 1970's to early 80's type oral inflator with standard 1" OD hose end. The oral end is about 15/16" OD. I think it's Seaquest or Seatec, and seems to be sealing and working ok. If I recall there is probably a replaceable oring seal in this, but I haven't opened it up. It is missing its original rubber mouthpiece, but one could be easily fabricated from some rubber hose to keep you from whacking your front teeth with the hard plastic body.
Email me if this looks like something you could use.