I've got a lead on a Hetchins Experto Crede with straight stays which I believe was from the 50s, about 21&1/2" in size, plus two other frames, the first a 1954-55 Flying Scot track frame, 21&1/2" with chrome lugs and stays & a Claude Butler track frame most likely similar in size. I've not seen jpgs of any of these, so I can't speak to the frames themselves, as I'm dealing with this contact in the U.K. on another purchase, but he seems like a fair person and very honest fellow to deal with.
If anyone on the list is interested in one of these frames, please email me offlist, and I'll supply you with the contact information.
Peter Naiman
Glendale, WI