Thanks everyone. They didn't ask me to send it back and we didn't discuss what happens on the other end of the sale.
I got the impression that eBay is going to eat the money that they just reimbursed me, but I don't know if ultimately they'll charge her for it or not. From talking to the woman at customer service, everything I (we) have been saying the whole time applied. There was a do-not-return, at no point did I invite her to return it (in fact the record showed that I repeatedly told her not to send it back), and she found nothing misleading or unclear about the listing.
So, it leads me to think that a lot of eBay's reputation as being buyer-centric probably comes from less qualified people deciding on these cases and then sellers not following up - but that's just speculation based on my experience of course.
Once it became clear to the rep I spoke with that the item was as described and the no-returns policy was in place, it was a clear cut case of buyer's remorse and the buyer had inappropriately accused me of selling something that wasn't as described to abuse the buyer protection policy.
I'm assuming I won't have any contact with the buyer from here on out, and I'll never find out if she's going to pay that money or not, but all's well on my end.
