Didn't Svosh make a skin that had HK pretty banged up?
Yeah, that's my favourite HK-47 re-skin.
Keiko's is still very interesting, and only needs a little tweeking to make it great, IMO. The balance and contrast of the red rust to grey metal works really well.
I'm not sure if it is possible to do skins that aren't symmetrical. If you can, I think it would require some coding.
Actually it only requires editing the UVW map in gmax. As for HK-47, he already has a lot of non-mirrored areas. You can see in Keiko's screenshots that his face and chest plate (where the bullet holes are), aren't mirrored. On the chest, just below the hole there are two rectangles on only one side of the plate, and the rust on his face is mostly on his right (screen left). There is still a lot of his skin that is mirrored, but not in the areas that Keiko drilled some holes into him. :snipe1:
EDIT: Here are the Wookieepedia pages for slugthrowers (
http://starwars.wikia.com/wiki/Slugthrower) and bowcasters (
http://starwars.wikia.com/wiki/Bowcaster).