While we're still on the subject:
Discovered these two stays in a Gothenburg museum's database (unfortunately not of great use if you don't know Swedish).
The pictures were taken in late 2009, which indicates that they're in the progress of digitalizing the collection to a greater degree - woohoo! A lot of their objects don't have pictures as of now, but maybe that's about to change?
Anyway; I'll do my best to translate the museum's description of these stays to you:
Linen stays (click link for additional views)
Stays of natural linen (and cotton?) with springs of wood and baleen sewn in. The model gives a smooth front and flattens the bosom. The lower edge of the stays is tabbed and bound with white leather. Shoulder straps, circa cm wide, are tied to the front pieces with plain ribbon. On each shoulder is a thin sewn-on brass grommet. The top edges are only basted together. Laced in front with pairs of eyelets. Lining of coarse natural linen.
Silk stays (click for additional pics)
Stays of yellow silk rep with springs sewn in. The stays are made from two different qualities of silk with different [weaving term; don't know the apt translation. Something about thickness of weft?] that have been combined for a decorative effect. The lower edge has sewn tabs and the model gives a straight posture with a flat bust. The springs go down past the hips and up and form open shoulder straps that are tied over the shoulders. Springs partly made of wood. The bodice is partly open in the front which is shaped with horizontal, triangular tabs that fasten at centre front with hooks and eyes. Laces in back, pairs of eyelets for spiral lacing. Binding of yellow silk ribbon and natural linen. Lining of natural linen. The armscyes are reinforced in the back edge on both sides of the bodice.
If the text sounds somewhat confusing I must add that it's not completely my fault although, my translation probably is a bit mangled. I tried to translate it word by word. For example they used the term "fjädrar" when referring to boning, which I see much more fit for corsets of later eras (like Victorian) so I translated it to springs although boning is more appropriate for garments of this type. If I make any sense at all - I'm afraid I'm lacking a lot of sleep today!
ETA: Is it bad that the Google translations (1, 2) only are a teensy bit worse than mine?