This is fascinating: I've been writing a very (and I mean very) similar library that also uses the concept of a Parallel DOM (dependents, views updating on a 'data' property, nodes named by standard ids, all child nodes with IDs scanned for and bound to a property), I had just decided to create the concept of 'Keypaths' as my events were clashing on ids.

The thing I have that I can't see here is a selecting/switching node: essentially a page or a tab that holds multiple states but only presents one at a time.

Thus makes me very happy and very sad: happy as I don't have to write all things things now; sad becasue I don't get to write all these things now.