Well, I actually ended up taking a bit of a different tac. I did the "gluing" working inside of ColladaParser instead of outside. To accomplish this, I only had to pass in some extra parser information to the ColladaParser (which again, I've expanded on my end).
However, you could still use Mesh.extra to pass whatever data you like back from a custom parser, and then use that to "link" things together. Either way works probably. It's sort of hard to generalize this enough to be useful for everyone. -Dave
