3D items are unable to be added into the game by regular users, since we would like to keep all those items looking good. And have at least some kind of quality control regarding them. Some regular users may create and sell some abominations. Among other reasons.
Multiple hair styles being used at once, was also removed since it caused some glitches with some hairs being worn together. So it was decided to remove that.
Of course, I'm sure what Kido said probably still works.