Looking for isolation suggestions...

Neuance shelves will improve coherence without changing spectral tilt nor squash detail. Worth a shot.

This sounds like it used to be me talking to myself:

I probably have all the resolution anyone on this planet would ever want. I would like something rich sounding, excellent bass performance is a must as well

Use a Zoethecus Z-Slab shelf - these are available at relatively low cost from Stewart at SOS, & will bring out that rich warm bass performance that you're seeking, while not degrading the HF resolution which you've achieved. Click on my username & scroll down under the bio to learn more about how this shelf is setup in my system's digital stack.

Try Aurios MIB Pros with the tungsten carbide balls. These beasts worked wonders in my system. I have them under all my components. You still need to place them on something but my experience is that they do not have to be placed on highest quality shelves because they insulate so well (I lean towards the complete isolation school of thought rather than the coupling/draining vibration yada yada schools of thought).

From what you describe, though, I am wondering whether you should not also look at the digitial ICs or the support of the CD drive (assuming an Audio Synthesis DAX Discrete DAC is indeed a digital/analog converter as its name suggests) in order to get the type of sound you want.

Hpshps, I am waiting for a modified Pioneer transport before getting too involved with tuning this unit. I do have Ganymede V.C.S. roller bearings under my current transport. As for the digital cable I am currently using a Stealth Fineline Mk II. My new transport will allow for a proprietary connection. I am currently using some mahogany blocks under the DAC. These proved to be much better than some small DH Cones that I tried prior to the wood blocks.

Unfortunately I designed my rack with the assumption that I would be using a 1-box player, so the 2" height limitation is a requirement.

Thanks to everyone offering suggestions.