I am not quite sure what you are asking? A sound proof floor?
Could you some how get thick styrofoam sheets from a hardware store or something, then get a peice of plywoood and use a sheet of linoleum (or use chloroplast)?
I would think a hardware store, like Home Depot, would have some sheets of styrofoam from having things shipped in. You could ask them, I think that would block the noise of the bunnies thumping or rolling toys around on the floor, since the foam would act as a noise barrier.
You'd have to go out and buy the plywood and chloroplast, but the foam should be free if they have some to throw out anyway!