I think the response on the M3 skins was they were waiting on the M3 to be updated. As is, there were problems with getting stuff to show up properly, either being distorted or just, for lack of a better word, wrong. Only the skinners could say what the real reason is. Do correct me if I'm wrong though.
But on a side not, I do agree. I would like to see skins for the M3, M16 and the M8. Even the Jeep could probably get a skin. Can't leave out the Wirble and Ost either.