According to this tutorial: http://www.thesimsresource.com/article/tutorials/wdstutorial, I had an idea about a plugin which does that mesh finding and extract them and does everything till step 28.
So as step 29 we can open our 3dmodelling program and edit the meshes.

That's for clothing, but it's possible to write program to do it for hair and other meshes I think.

The sims2 meshing life would be much more easyer and ejoyable that way.

I know very little about C and visualC or Visual basic or windows assembly, and I've never wrote plugins before, but I hope I can write it, if some simpe developer help me. I've written much prgorams, but mostly in rexx, because I prefer text base stuff, because it's easy to read, write, and modify. I've never coplied a C script (while Linux make installs not counts :D )

Oh of course, it could be more usefull, if you create another option in simpe wizard like recolors, just now it's for example will be Hair meshes