No idea, but my 6U's are heavily modified - power, custom ventilation, mixed media decoration. Why? For the same reason, I build custom PC's when others buy them off the shelf.
a. I've run completely stock -full 6U cases and had zero heat problems. And I've tested them with the same gear I use to do heat map, airflow, and ventilation design for the PCs.
b. Working to make some custom powder-coated blanks with varying ventilation designs and colors in useful hp sizes, but covid and paying projects have slowed things down a tad.
-- Vow3ll
Badass man! do you have any videos of your 6U mods?
JB