My friend Bhil had a cat with thumbs, named Mr. Feet. Fully opposable with three claws on each thumb. Also another seven toes on each front foot and eleven on each back foot (but no thumbs there). So forty-two claws total.
Sadly (or perhaps fortunately for the human species) Mr. Feet was dumb as a post. Probably the least intelligent feline I ever met. It was pretty neat to see him carrying around a live, wildly buzzing cicada enveloped in his big hairy fist, though.