Isolation feet/pads with minimal verticle height

I just had a cabinet built to house all of my audio equipment. One each shelf, I have two to three compenents stacked one on top of the other, and verticle space is at a premium. I have had to remove some of the rubber feet from several components and replace them with adheivsive-backed plastic feet (with a verticle height of only about .25") in order to fit the components into the cabinet. Unfortunately, I have noticed that the sound (particularly from the CD player) has become harsh, and rather bright. I'm sure that using some sort of isolation device below the CD player will certainly improve the condition, but available height within the cabinet is a problem.

I'm looking for suggestions on what I can use as isolation "pads". Additionally, can "pads" be used at the bottom of say two or three stacked components, and have benificial effects on the top component, or must each component be separated with its own isolation "pad" (which obviously requires additional verticle space). I know about cones, pucks, and bearings, but all of these are far too large vertically. I need something with a minimal top to bottom height.

Any suggestions you may have on either a commercially available product of a "do-it-yourself" solution would be greatly appreciated. Thanks, Ken G.