Some progress, yes.
Of course, I have other responsibilities IRL as well, but I try to code on this whenever I have free time. The point is that the first steps were probably the easiest. I can give a heads up on progress so far though:
* I have figured out a couple of additional bytes of the mesh as well as discovered completely new chunk types in certain mesh files that need to be figured out as well.
* I've also looked at animations; the structure of those files is the same as that of the model files, but I still need to figure out how to interpret the actual animation data.
* The viewer now also displays the mesh' bounding box (located in previously unknown data), almost displays bones correctly, and a dialog that shows the model's detailed information is almost finished as well.
I'll see about making that new version public when those things work because it contains bones and polygon counts, something I'm sure plenty of modelers are interested in.
However, an importer/exporter is still quite some time away. Particularly because I need to understand every bit of both model files and animations files.
PS: I thought I'd mention this: it turns out my viewer showed all models mirrored. I found out about this when looking at the Stormtrooper. The bones say the gun is connected to his right hand, but when looking at the rendering, the gun was connected to his left hand. Didn't take long to realize I needed to use a right-handed coordinate system instead of the left-handed one I was using.
And by the way, 3D Studio Max also uses a right-handed coordinate system. Coincidence?