I am pretty sure lifting foils on a cat will make us even faster. And a catamaran is an ideal platform for foiling with its light weight and wide platform. There has been several tests with lifting foils on cats, and they are really fast when they get them to work. Dave Carlson (dacarls on this forum) has a webpage with lifting ladder foils in practical use.
But not everybody will think a foiling cat is still a cat, and do we really want to go in that direction? Lifting "banana" foils might be acceptable to most of us tough, and I think we will see them in common use soon.