> Well the tag name on each volume element of the iMesh instance within a PyNE Mesh is ve_idx. 

Really?  Does that come from us or from PyTAPS?

> In any case, I think we have more serious API issues to sort out. This PR might not even be what we want. I will be happy to change variable names once things start to fall into place a bit better :)

Definitely.  We aren't speaking the same dialect yet.  :)