Looking for the good oil.
That is what we recommend you buy. In this place, people often recommend expensive stuff. I am going to guess that you do not speak English as your native language, and that this idea is a direct translation of your language slang.
Custom SFF case
ATX Z68 board
45w SB Xeon w/onboard graphics
2 x SSD
4 x 1TB 2.5" WD Blue
4 x slow 120mm fans
2 x PCI cards that run hot so must draw a lot
3 x PCIe cards (10gbe and two 11n)
Wow, 5 expansion cards, 6 drives, and 4 fans in a SFF case?
(How small can a SFF case be when it is holding that much stuff that "run hot"?)
Sounds like you need a full tower case or a rack-mount super-server case.
Will add another 2 x PCIe cards (10gbe and dual port 1gbe)
I believe that most 10 Gbe cards run really hot. Cards that have optical fiber output are normally put into rack mount cases, as moving the computer could damage the fiber. Over flexible wires 10 Gbe/T only runs over short distances of about 15 meters. (AFAIR)
I guess my question is can these pico PSUs handle a lot of PCI express cards?
The pico PSUs have a rated output power. This is usually in the product name. For example PICOPSU-150-XT
, is a Pico PSU with an output of up to 150 watts. It will regulate its output to keep voltages correct when the computer draws under 150 watts.
PCI express 16x cards can draw up to 75 watts through the motherboard connector. Cards need to use power directly from the power supply (via 6 pin and 8 pin connectors that supply 12v) to bridge the gap from 75 watts up to the 250 watt limit in the PCI express specification.
I don't know why you want to use an external PSU with so much hardware. If your computer is going to hold this many components, then you may want to also use an internal PSU. I guess this odd (perhaps incorrect) configuration is why the case will have to be custom.
My worry is the different rails, I forget the specifics but I was looking at the canadian 24v medical board with a 180w ish psu.
Are you being forced to use a 24v power supply due to the computer being part of medical equipment?
If that is correct, you may want to employ a DC-to-DC power supply to covert that 24v down to 12v. You can power your motherboard off of a wide-input Pico PSU like the pico-PSU-120WI-25V
it can supply up to 120 watts.
The people who make the Pico PSU also make a DC-to-DC coverter called the DCDC-USB.
It can supply another 120 watts at 12v that you could connect to a 6-pin PCI express power lead, if any of your cards require direct power.
I don't understand how these different parts of your post are connected. You will have to elaborate if you want more effective advice.