The pods are fairly soft, not particularly rigid.

Can you post a picture of the shrub?

I'm afraid I didn't get a picture of the shrub. It was about 6 feet tall, and the branch structure was fairly open. No exfoliating bark that I noticed. Single trunk, no sign of new canes being sent up from the root mass.

It could also have been a reasonably young tree, I suppose.

Some of those pods look a lot like okra, do you suppose it was some form of hibiscus?

The two common hibiscus that are hardy in my area (hibiscus syriacus and the hybrid hardy hibiscus plants) have seed pods that are significantly thinner and more paper-like. Despite being reasonably soft, these pods were thicker than those. Hibiscus seed pods are also more pointy, even star-shaped as they age and start to open up. These are brown and dried and still sealed.

I don't think there is another shrub-size hibiscus in my area, other than hibiscus syriacus, is there?

Oh, there are many species, but if you don't think the "shrub" itself looked like a herbaceous hibiscus, we can probably stop there.

Consider Calycanthus floridus or occidentalis.

That is a good suggestion! Calycanthus pods hang down... unlike Hibiscus pods.

I remember opening a pod on one shrub and a wasp came out! It was a good place for him to hide.

I was also thinking Calycanthus.

I've grown them from seed from pods that look exactly like that. Everyone should try that although unless seeds are cracked to let water in, germination may be very long. One of the most interesting seedlings emerging that I have ever seen as 2 immense cotyledons pop up curled into a tight spiral like a cigar and then slowly unfurl.

I believe it is Calycanthus. Interestingly enough, that was my first guess when I saw them, but I ruled it out because in my memory Calycanthus seed pods looked a bit different. Googling them, however, makes me wonder what I was actually remembering! Google's image search confirms Calycanthus, at least for me. Thank you all!