While you can use the Alpha channels to make the hair shorter, it takes a new mesh to make hair longer. Longer hair on the men is one of the meshes that people have really been wishing for. But so far it's a no-go. The meshes are made using Maya. We'll need instructions or a "mesh making" program from Maxis in order to make our own. (Even if you know Maya, it doesn't mean that you have all the necessary information on how to make it fit the parameters of the game.)
I think the primary thing is that we need to be able to decrypt the .package files properly. The meshes are in there and so far, I've seen the XML Coding for the meshes, however have had no luck trying to get the files out so I can modify in Milkshape.
If you figure how to do it in Milkshape PLEASE make a tutorial! I have Milkshape too and know how to use it better than the other 3D program I got and haven't figured out yet...