.40-90 Peabody What Cheer

I and several fellow enthusiasts are on a hunt for a .40-90
Peabody What Cheer cartridge or fired case. We are most anxious to obtain an example
for brief study only,
as we wish to have a chambering reamer ground to the original Peabody configuration.
Once proper exterior dimensions are taken, the cartridge would be returned, resold,
whatever the owner preferred. I would be happy to rent the cartridge for a few days,
post a safety deposit or whatever else its owner would require. Do any of you have this
cartridge, or know of anyone who does? I would literally handle it with white cotton
gloves and return it promptly, insured.
I have reviewed several reamer specifications that purport to duplicate various
What Cheer cartridges, and they invariably replace the curved shoulder and neck
radii of the Peabody originals with more conventional bottleneck specs. We wish
to avoid this error.
Thanks for any responses.

I have secured the loan of an original for study from a fellow collector. Really appreciate the help.