Kind of makes you wonder why he doesn't have one already...
In case you haven't realized; this would be for TSL.
SO! *claps hands together* We all (should) know about Mira's wrist launcher that can only be used by her. Or, with a mod or the KSE, your PC as well. I really wonder why no attempt was made to give HK one of those. We all know it would make him even more bad@$$ then he already was.
So, the launcher uses a special animation with it's pathetic meatbag user. However, HK-47 possesses an animation used whenever he makes use of a flame thrower, carbonite projector, stun ray, shield disrupter, and so on and so forth. Just have it shoot the rockets and darts instead of the various assorted rays and beams. I think that would be an adequate substitute for the normal launcher animation. I have no idea of what all you'd need to do, but you'd probably want to restrict the use of the item to HK. (We wouldn't want T3 to get any Super-Droid ideas, would we?
) Anywho, I have no idea how one would go about doing this, but I thought it would be good to suggest it.
Interjection: Silence, meatbag! *blaster shot*