No I have not seen this, but it looks awesome and like a great place to start. This structure is pretty much exactly what I envisioned at a high level. It would be even more useful if there were a finer degree of granularity between concepts, and each vertex actually directly linked to a video. I think the killer feature for a partially ordered learning resource is going to be keeping people within the ecosystem (i.e. watching embedded videos or reading embedded articles/guides/etc.) so they can grind out on your website, not repeatedly have to go to other websites where they may get distracted or become reluctant to return to the original.

Really appreciate the links