Audio Rack Selection

I also HIGHLY recommend Core Audio Designs. I have 2 of their racks and use them on hard wood floors. They are not only built incredibly well and perform incredibly well but they are the best looking racks out there. The wood is beautiful as is the craftsmanship. They are not tecky and tacky looking like most high end racks. 

Adona has been producing solid racks and multilayer audio platforms for many years. Changed from my long time Billy Bags rack to an Adonis Eris 6W with cherry trim. Beautiful and solid.  http://www.adonacorporation.com/modular.html

why do people think any custom woodworker can design and produce a high quality audio rack engineered to enhance sonic qualities of your audio gear?  Sure it may look nice and it could end up being heavy but lets be honest, it's just furniture and not an engineered piece of gear.  Just understand what your goals are here.

But what if you have an audiophile with carpenter skills who can build the same rack as a non audiophile? Does one need to go to NASA or be trained there to determine what's the best solution?

A lot of this is nitpicking in the extreme

All the best,
Nonoise

Just constrained layer damping, nonoise. That, and an irregular shape.

Some few materials have constrained layer damping built in, like Panzerholz, or, to a lesser extent, slate, or Baltic birch plywood. The trick is to put two materials with different speeds of sound, in intimate contact, like hardwood and elastomeric glue. I used 2 1/2" of Baltic birch in three layers, bonded with elastomeric glue, bonded to a topping consisting of an inch of slate. Slate itself consists of very thin layers of rock, which reduce sound transmission and resonance.

The very best shelve material is Panzerholz, which I used in the plinth of my DIY turntable. So I have three different non-resonant materials, with different properties, which prevent resonance.