I've thought about this often, up to & including pricing a small sandblasting setup for grates & other parts.......
Never proceeded, usually how I approach grates is to scrape them down real good & cook a heap of 'turds to coat them down in bacon, sorta like cast iron.......
I've also heard sterling reviews of the stainless steel grates, but do not have any as of yet.....
Any kind of plating or coating ( like powder coating / ceramic aluminized coating / chrome plating ) needs to be pretty much spotless going into the people's tanks or it will leave nasty residue in / on their equipment, so I don't think re-plating would be worth the time, etc. it would take to do up right
You could check with a sandblaster to see if they could do a batch of them at once, then an auto plating place for the same batch, grouping up MIGHT make it do-able.....