
OK, just for grins:
- Kekule hypothesized a resonant structure for the aromatic benzene
ring after waking from a dream in which a snake was swallowing his tail.
- Archimedes formalized the principle of buoyancy while meditating in
his bath.

In neither case was there "no connection to prior theories, concepts, etc."
as you stipulated above. What there was was an intuitive leap beyond
the current way of thinking, to develop ideas which subsequently proved
to have predictive power (e.g., they stood the test of experimental
verification).

pardon my kibbutzing...