[SuperPaintMan]

This sounds very similar to Xanadus concept of Transclusion, I'm kind of sad this kind of context-preserving inclusion never really made it into the modern web. But due to the nature of Xanadus fixed and versioned documents, transclusions can't be broken. :(

[hashhar]

Metabrainz and their wiki/documentation/data sites do this. See https://musicbrainz.org/doc/WikiDocs for how they implement it.

[FigmentEngine]

my POC of this http://hyperion.figmentengine.com/