@evan
I hope you don't mind me thinking aloud here - despite my original post, I actually *do* want to build for ActivityPub. That's the source of my frustration.
Come to think of it, I don't need to serve up-to-date representations of all objects, only locally sourced ones, and those are easy to assign an owning app.
So, the apps would simply register a new object and the AP server would the direct queries for the object to it.
Hmm, onwards it seems.