From that thread:
Rim brakes even wear chrome plated rims. What you are looking for is not possible. All it takes is one tiny speck of grit between the pad and rim and the powder coat will get scratched. Then the scratches just get filled with pad material and other muck.
Which is probably why my rim was machined in a week being that I was riding it in the middle of the winter with all the salt and grime.