By existing, do you mean puddinpop's? I'm already using that, so it'd be easy to get a head start mining with the GUI. I'm game to try whatever you throw in, anyway. The problem is, I'm about to log off of consciousness, shortly.
Would you have to worry about taskbars displaying icons larger than 16x16? Also, The translucent sections I'm looking at in the icon are white with a teeny tiny opacity. (255,255,255,1) Oh wait, I see the problem. The 1-bit transparency plane is all set to zero. Some of that should be marked transparent, perhaps alpha != 255.
EDIT: Got this taken care of, I just pull the 16x16 icon out of the icon bundle and explicitly give that one to the taskbar. I also had to hand-edit the 16x16 icon since it was giving translucent pixels and apparently those actually mean "be really dark". After taking those out, it looks fine now 
Would you have to worry about taskbars displaying icons larger than 16x16? Also, The translucent sections I'm looking at in the icon are white with a teeny tiny opacity. (255,255,255,1) Oh wait, I see the problem. The 1-bit transparency plane is all set to zero. Some of that should be marked transparent, perhaps alpha != 255.