I suggest passing this on to the devs of wineskin, a mac-based wine wrapper. Perhaps it could be added to a subsection of winetricks, too. It would need to be thoroughly tested of course...
I am very much a newbie. But, if you have some bug-testing you need a guinea-pig for, and a well-written set of instructions, I'm available.
Also, ICNS is already implemented in Wine? Or what's the status if I needed to access it myself?