[comex]

I don't think that's much better than Flyweight in terms of intrinsic meaning. A little better, since it breaks down into hash + consing, but having not heard of either before, I wasn't able to easily guess what it was despite knowing what hashes and cons cells are. Of course, like everything else in Lisp it predates GoF, so I suppose it would have been nice to reuse existing jargon... But maybe a better name would be "memoized construction".

[catnaroek]

“Memoized construction” is a very good name, indeed. It's actually better than “hash consing”, because it isn't tied to a particular implementation strategy. But I think the “handrolled” part is also important, to stress that it isn't something the language implementation gives you for free.