I re-built my NAS, and it has a 600W PSU with some old hardware (BIOSTAR A880G, Phenom II X3 but X4 unlocked :p). The PSU I know got a little warm under load as I had it on a VR computer before, but it’s nothing but cool air on this NAS so I figured it has plenty of power to spare for other stuff.
I figured since Molex has 12V and 5V, that my network equipment all used 12V barrels, and that the makeshift fans slapped on them I had at 5V to be quiet, that I had the perfect set-up to just power it all from my server. I don’t know how to use a multi-meter and went with some paint on the wires themselves, and only took out one spare router 
(turns out I’ve been lucky all these years with doing it like that and that there’s no guarantee with the paint on the wires); a quick wire flip on that one barrel and everything was cool. The Molex end came from a SATA power convert adapter, and I heard more than enough stories to know I didn’t need to have that lying around
I don’t know if it’ll win for appearances, but it all works great!