For chrome, I always liked Model Master chrome. It had that special luster. In the last couple of years I've used the Molotow chrome paint pens, which *really* look like chrome. For stainless, probably your best bet is one of the AK Interactive paints, but I don't know how well they'd do with a brush. Tamiya or Vallejo comes to mind. Some of my metallic Vallejo colors are actually pretty nice. Especially if you add a drop or two of an acrylic paint retarder.
I just bought some Mirror chrome paint from Culture Hustle. It looks amazing, and I think once it has cured you can touch it. I may experiment with shooting it with a coat of semi-flat clear to see if it ends up looking like stainless.