It hasn't been done yet. Or has it?
Old Amiga Icons are different size between folders and applications and on AROS there would create a disalliance very ugly to see.
Also for Amiga Icons to put them in the distro you have to get permission from the rights owners, if you wanted you could convert them to DualPNG, but again I think you would need permission.
Then on my Distribution it would be impossible since it includes almost 1000 Icons all different from each other, finding the equivalents on Amiga would be a feat.