I searched extensively a few years ago and all the "metal" ones still have plastic innards.
I second the hanging bar soap idea. My mum has crocheted holders for her soap in the
shower. It's that fairly thin crochet cotten, and crocheted as a net rather than a solid piece. That lets the whole thing dry out between uses so the soap doesn't dissolve away. You could use one of those mesh bags onions and oranges and stuff come in to keep the soap
dryer, too. It wouldn't get you away from plastic but at least you'd be reusing something... assuming any of your produce comes in those bags.
I just have plastic pumps. I bought a couple from a
local soap company and have been using and refilling them for years. You can blend up your little bar soap bits with water and use them in the pumps, too.