that was one appeal of that n2800 intel atom board. atx voltages are broken out onboard so you give the board just an 18v laptop supply and the board (from intel, which I trust to not use fake parts) does all the important voltage regulation.
I like to minimize failure contact points. so the m-sata drive 'bay' is a must-have for me, the onboard psu is, and if I can avoid having any option modules dangling from wires (like sata drives or pci-e cards) so much the better. the atom cpu is soldered on, so no worries about sockets. its heatsink is designed by the manuf, so no guesswork there. its as industrial as you can get while still being consumer priced.
its an old model, though. probably not buyable anymore, but it gives an idea of what to look for, in a mini-itx. the less connections you have, the better. one of my n2800's is my pfSense firewall. throw it in a corner and forget it, just what you want.