You're best bet would be emailing to architectural salvage/antique stores across the U.S. Finding something similar would work also. Southern Accents Architectural Antiques is one I am familiar with locally. Olde Good Things has several locations.

Similar, I don't know why the link says Duncan, it's called Wentworth

https://www.rejuvenation.com/catalog/products/duncan

Could you rob enough escutcheons from the inside of closet doors to get by?

So's your ideabook.

Here are ten sets of metal knobs with the backplate in the basic shield shape, in a darkened finish. They are not the same.

The reason these are not reproduced often is that the plate is too narrow to cover a modern cylindrical door prep.

https://www.thepreservationstation.com/antique-hardware/complete-door-hardware-sets/antique-art-deco-door-hardware-sets-c-1930s.html