My understanding of AMVs has been from an outsider's perspective. I didn't really register AMVs as something more than a flurry of images and sound. jbone's Let Them Eat Rei really was what caught my eye, which is why it starts the video.
Honestly speaking, I can't say much about AMVs and folklore; I don't know them well enough to say anything. However, I noticed that over the course of looking through AMVs, I did realise that a significant portion of them spend weeks to months on an AMV. The editing and motion graphic level of a lot of pieces is incredibly high.
A cursory glance at AnimeMusicVideos.org's forums shows subsections devoted to editing. I don't know much about the community, but I can see a hugely and wonderfully inclusive scene. A very technical and skilled group of people.
That's all I can say, really. I think the works speak for themselves.