Here's short instructions on how I figured out to do this today. I knew how to get the textures but had no idea how to get the mesh, so yh.
-------------------------------------SIMS 2
I just got "SimPE" the sims2 package editor.
http://sims.ambertation.de/en/download/
Then I opened the ".package" file downloaded from a sims2 site.
------Getting the 3D body---------
To extract the 3d body you need to use a sim2 package with a mesh file in it.
Click on the list of files that says GMDC, and on the lower left check all the parts in that box that says "Generic Rcol Editor"
Click on preview to see a small image of what it looks like.
Then