The Fractal Design Define R cases can house a lot of hard drives, but they are kind of big. My Define R6 can theoretically house 11 3.5" drives iirc in addition to 4x 2.5" but it does not come with that many drive sleds out of the box. For the 2.5" drives only 2 sleds are included. I think for the 3.5" it was about 6.

Not a valid option if you are looking specifically for lossless music