I'm not a pro, but I don't believe such a thing exists. A flange is supposed to rest on top of the finished floor and be screwed to the subfloor. This is to allow the flange to seal with the wax ring, and to keep the toilet stationary by bolting it to the flange. Obviously, if the flange is not solidly secured to the floor, neither of these goals can be accomplished. Rather that trying to make the raised flange work, I would suggest you lower the flange to set on the floor.