Materials to reduce sidewall flex & vibration ?


I am wishing to reduce sidewall vibration without adding reinforcement 
within the cabinet. I'm curious about fiberglass and other products that can attach/bond 
permanently to the sides yielding the highest stiffness to weight ratio.
ptss
No Rez, designed by Danny Richie of GR Research. It is expressly for absorbing speaker enclosure wall resonance, being installed on the interior of the enclosure's panels. Very effective.
Thanks bdp24; however, in this case I'm only interested with
material that can be bonded to the exterior of the speaker. I'm hoping 
some have experience in materials such as fiberglass and carbon fiber
as well as with granite,etc. 
You could certainly go with granite, finding a really good installer to cut and glue the sides and top. Corian could certainly be tastefully done as well.a bit easier to do a cutout in the front for the speakers as well. If it works really well you could start a business.