Custom Racks They are made of seriously thick maple and walnut. The cost for each was about $1900 dollars. They are quite heavy and extremely rigid. The vibration transfer is extremely low. These have been the best improvement to my system EVER. I suggest that you talk with Mike at Custom Racks listed here on Audiogon under furniture. They can
pretty much custom make exactly what you want.
FYI, I have no connection with this company.