I recall speaking with a team in the Tesla Division that had intended to powder coat their robot but discovered that their design had not taken into account the thickness of the coating so they skipped it. They ended up applying a "brushed finish" that looked like it was applied using a Scotch-Brite pad. Since it consists of a series of randomly oriented fine scratches, scratches don't really show up prominently. It looked sort of like the photo in the link below.
http://www.quickshipmetals.com/decor...-steel-rs.html