The interview went well. We laughed a lot and I think they like me fine.
The biggest question wasn't "am I qualified" but rather "am I a good fit for the firm?" I have specialized in larger projects and this company does lots of little ones. I really am well suited to larger projects too, since my attention span is longer than most (in this field) and I enjoy working on a team. I can adapt, certainly, and working on smaller projects makes me more well-rounded...
I liked my old job, dammit!
(Edited to add: Fear not, I didn't put out these kinds of ruminations during the interview. I tried to stay upbeat and crowd-pleasing.
I'm happy to say though, that the people who interviewed me asked some great questions and will probably do an excellent job of choosing a new hire.)