There are some galleries in SL that feature different artists. This blog features a lot of the nicer creations people've done, both 2d art and 3d: Not Possible IRL
You can design custom skins to order (there's a downloadable template), as well as clothing, tattoos, etc, that apply as different layers onto the avatar mesh, but what most people do is design something, sell it with copy/no transfer permissions and that way they keep making money on the product even after they've finished the work. I've had friends as well who've designed something custom and then modified it for mass sale.
I started using Malachi 3 years ago when I joined Second Life. It's from the biblical name, not Children of the Corn. It's in contrast to Rothschild which is a much more modern Jewish name.