Looking for recommendations for under desk computer mount (AKA “CPU” holder). It needs to support medium tower with dimensions of W 230mm, H 460mm, D 520mm and load / weight of ~25-30kg (not too sure ...

The Mobile Pro Desk Mount Combo (US$239.95) is part of a range of monitor mounts from Bretford, specifically designed to compliment the iMac (with built-in VESA adapter) and the Thunderbolt Display.