The c1800 stays from the Ohio Historical Society are actually 1830's according to their website.

http://web2.ohiohistory.org/ipac20/ipac.jsp?session=130C432174R56.4654&profile=museum&source=~!horizon&view=subscriptionsummary&uri=full=3100001~!178553~!32&ri=4&aspect=subtab73&menu=search&ipp=20&spp=20&staffonly=&term=corset&index=.MG&uindex=&aspect=subtab73&menu=search&ri=4

Great analysis! The only trouble is that, as you mentioned, the museum dates aren't always correct - while I generally trust 1810-1820 dates, I'm not so sure that a lot of the ones that are dated earlier are correct.

Thank you for all those links to specific stays, though! Especially the so-called Kent State short stays: I hadn't been able to find a picture since the one on the KSU site was taken down.

The OHS date of 1830s isn't necessarily right either. I'm not saying it's earlier than that but there aren't clear enough photos to be 100% certain.
One thing I've learned from looking at all the ones I could find is that museum dating isn't always accurate. The Philadelphia museum has stays dated 1810-1830, and personally I'm convinced they're no earlier than 1830 due to the depth of the gussets.

Three more for you, from an online Italian source:

I've always wanted to duplicate this very simple short stays: http://www.abitiantichi.it/collezione/busti/busto36.html

And two long stays, one brown an one white:
http://www.abitiantichi.it/collezione/busti/busto41.html
http://www.abitiantichi.it/collezione/busti/busto17.html


This overview is fantastic! Thank you very much!

Oh, sorry, there's a little information on those stays on the main display page, almost all the way to the bottom: http://www.abitiantichi.it/collezione/coll1800-40.html

Thank you so much for this article, so many links and photos, so much good thought put into it! I really appreciate it.