You could try Vibrapods, that's what I use between my floorstanders and a piece of laminated glass on carpet over hardwood, suspended floor. Sounds very good to me.
http://www.soundstage.com/synergize/synergize011999.htm
http://www.vibrapod.com/Reviews/tas.htm
http://www.soundstage.com/synergize/synergize011999.htm
http://www.vibrapod.com/Reviews/tas.htm