Cheiron,
Your post about body art (tattoos, piercing, scarification, etc.) was
fascinating. The roots of these practices among dragonewts and trolls is an
interesting hypothesis. I can see a lot of colourful potential in this. The
topic needs more research, but I believe you are on the right track.
As for the elvish practices of pruning and grafting, my players can provide
eye-witness testimony to elves having inflicted painful ritual grafting
practices on captives.