If what you said about meshes
Being handled
Differently in blender 2.63 then I might as well rewrite the code
Anyways. I have a pretty good start and like you
Just said I will have a repo up.
How were you creating the mesh? I'm not sure how to explain this, but how hard the upgrade is depends on what method was used to generate the mesh. By default, Blender uses ngons, referred to as "polygons". Before, it was only triangle/quad faces, now called "tessfaces". It's still possible to use faces, but the names for face-based types are different, and I think they can't be modified if ngons have already been generated for the mesh. Well, at least, I was never able to get changes to the UVs to persist when ngons existed.
from_pydata now generates a mesh using the ngon system. UVs in meshes with ngons work differently than tessfaces. I'm not sure if I can explain this correctly. Polygons are made up of "loops". UVs are assigned to entries corresponding to each loop. With tessfaces, UVs are assigned to entries corresponding to each face, all 3 or 4 UV coords for the face.