We don't yet, but have considered it a few times. It would be quite surprising if it's a big source of revenue, so has not been a big priority for us on those grounds, but I do think it would be cool.
Does the LessWrong team sell any merch, or have you considered doing it? Things like shirts, stickers, cute shoggoth plushies?
The reason I'm asking is that branded merch would be an easy way to let people find each other for rationalist meetups. If you see someone wearing a LessWrong shirt, you're probably in the right place[1].
I'm thinking of just bringing one of the books and leaving it on the table, but it seemed worth asking if there's anything else, especially since Lightcone seems to need money (who knows, maybe you'll sell 10,000 plushies and solve all of your funding problems!).
This is inspired by a local meetup, where the organizer always has a giant stuffed Pikachu with her.