Well, I put Pearl back in with Thumper this evening, and shortly after I did, she seemed to kind of flatten out on the cage floor for him (couldn't see her tail; he was already there). I still couldn't tell if he accomplished anything, but it looked a bit more promising than earlier today.
I left her in there a bit, and kept my eye on them in case things got dicey. He groomed her for a while, and then decided to have another go. Suddenly she decided she must find a way out, and began acting aggressively toward Thumper when he approached. She was so upset that I had to take him out of his cage and let him roam the porch, while I tried to coax her out. She was making these soft grunting noises.
When I reached my hand in, she would start making soft grunts again. I had to take it really slow, because I didn't know what she was going to do, and I really didn't want to get bitten.

She came to me a couple of times, but as soon as I made a move to pet her, she retreated. I was finally able to reach in and scratch her head a little, and talk to her. It was almost like she felt betrayed -- "How could you do this to me?!?" I finally worked up the nerve to try to pick her up, and she didn't resist, thank goodness!
I held her for a moment, and put her back in her side. She immediately retreated to the litter box. But I just went out there a while ago and offered her raisins, and she eagerly took them along with copious amounts of head scratching (on her icky wet fur that Thumper spent so much time licking!). I guess I'm forgiven.
I think maybe I'll put her in one more time in the morning, and be ready this time to take her out sooner.
The whole thing reminds me of Pepe LePew and that poor little cat!
"Ah, my sveet Pearl, you are ze most beautiful bunny in ze vorld, I have vaited for zees day..."
"Get away from me, you beast!"