I have two large silent fans: one in the power supply and one over the cpu in my monolithic 2007 PC.
How about a load of mini-itx boards suspended in cooking fat?
I agree in that most workstation units have are visually lack lustre. I was asking someone the other day why they don't wrap X model of iPhone in alumunium or titananium, and he said that it costs too much. But surely they are so small that it wouldn't hurt to add some luxury materials - a can of pop comes with a free alu can.
The design actually reminds me perhaps of a precursor to the R1 astromech droids (on the inside.)
https://www.google.com/search?q=rack+mount+mac+pro
Halfway down this page and it really appears a lot of people are just inventing reasons to have a problem with it.
The cylinder doesn't inform a way of using it, it invites multiple. I picture myself using it "sideways," half turned for easy access/cable management.
Rack mounting will require innovation as well, but imagine how densely you could pack them and how dynamic you could make the cooling.
A single fan in a workstation machine. Unbelievable.