Idea here is modifying from flex-ATX PSU with size 150x81.5x40.5mm, it's smaller than high power laptop brick (normal length is more than 200mm).
Modification points:
- Remove top cover and 40mm fan.
- Remove all cables, jump start PSU inboard.
- Install modular bracket but only 2x 8pin CPU
- Fabricate 3D ABS housing to hold 80mm silent fan on top side and PSU.
We get a 160x85x50mm 12V brick with power consumption up to 500W, silent air cooler, you can compare with Dell D22P-01 220W 12V brick with dimension: 9.5 x 6.6 x 2.1 inches (~240x160x50mm).