I looked through the forum here for a way to convert a gallery to a carousel, and didn't find anything that helped (or that I understood). But there seemed to be a lot of people who wanted something like this.

After a lot of jiggering, I put together something based on the Sortable Fancybox Gallery that actually seems to work. Well...I'm not going to put up a whole post on this if the world is going to roll its eyes at me--so far as I know, this is a long-settled issue. But if anyone wants to know what I did, I'd be glad to share it with them. And if anyone has a better solution...I'd be glad to share it with them.