Best Equipment Stand

Used Symposium rack.

Possibly the springy Gyrodeck suspension and your self-described springy floor are not made for each other.  In addition, no disrespect to the Mitchell, but your system is worthy of a turntable upgrade. You might consider the purchase of an unsuspended turntable which you can then pair with a high quality isolation shelf, like a Vibraplane or Minus K. (You don't want to pair a suspended tt with a second suspension.)  This is worth considering if wall mounting is impractical.  Remember too that wall mounting is not a panacea; strong structural vibrations will be transmitted into a wall mount, too. You might ask an architect to recommend a suitable wall in your home that is relatively isolated from structure-borne forces. In addition, FWIW, I have had good luck with Adona rack systems.  At least they used to be reasonable in cost for very high quality; I don't know where they fit in the cost continuum as of today.  Adding the mass of a heavy rack might help with your footfall problem, or it might not.

Tom, you mention the need to level.  I can understand that for your turntable, but remember that a three legged rack, such as the Star Sound Apprentice is alway with all three feet in contact. Of course the design of all the Star Sound devices is to get the vibration to the floor and to the Earth. They would not be good for foot falls. 

The old Stillpoints component stands and pipes can be used as a two level  rack that is fairly cheap using Ultra Minis. Stillpoint technology is somewhat helpful for footfalls. You would not want to go over two shelfs high, however. 

One thing that I would discourage is wooden shelving. It robs the music even worse than rubber. There always is wall shelving but I've never had any. Vibrations have such substantial impact on fidelity that you really need to consider them.

I would give a call to Star Sound Technologies and see what Robert would recommend in that situation.  I have all Star Sound Sistrum racks, speaker platforms, and amp platforms holding my equipment.  The sound was immediately stunning and the speakers got dramatically better in about 10-14 days.  My speakers were not supposed to be raised off the floor as the designer said it negatively would impact the sound.  Tried it both was several times and I have to say he was wrong--the Star Sound technology is phenominal.  This allowed me to sell off most of my room treatments as they no longer made a difference.   I'm on tile covering cement floor, so it's different, but maybe there's a chance. My former rack was similar to what you have.   I bought almost all of this used on Agon, so my price easily fit your criteria--new, probably not.

There has to be some mechanism for dealing with seismic type vibration. Even the strongest most inflexible design rack will simply transfer the structural vibration very efficiently. In the worst case the rack will amplify the problem. I can appreciate the desire to organize and showcase the system but for the best sound in most cases the components should be placed directly in the floor using, at a minimum, some sort of footers or at best a mass on spring device(s).