Have a look at this system
for some ideas. If your system will be power efficient enough, you could use a picoSPU 150W instead of the fanless ATX PSU used in that build.
Any particular reason for going completely fanless?
IMHO, most people who want completely fanless builds are going over the top for no reason. Decent fans at <400-500rpm are virtually silent and cannot be heard much over 30cm away (particularly when inside a case) but having one fan can help reduce temperatures by a fair amount for virtually no noise impact.
For reference, my main system in my sig has a single Scythe Slipstream 800rpm at 5V mounted on a Thermalright HR-01+ CPU heatsink. It's hardwired to 5V so I don't know the exact rpm but I guess that it is somewhere between 400rpm and 450rpm. Other parts are an SSD and a PW-200V laptop style fanless PSU, so the Slipstream is the only noise making component, and I cannot tell by listening whether the system is on, even at 2am on a quiet night.
With the motherboard out of the case, I can hear a very slight ticking noise from the fan with my ear right next to it, but that's it.
I've tested the system with the CPU fan unplugged and CPU load temps using Prime95 are >10 degrees C worse than with the fan on (and this is with an underclocked and undervolted E5200 at 2Ghz and 1.0V in BIOS).
My advice is to pick some decently power efficient components that will do the trick but plan for at least one low rpm fan either on the CPU heatsink or as a rear exhaust.
The Intel Clarksdale i3's or i5's would be a pretty good starting point for a system for your needs - I think the integrated graphics should be enough to handle any Linux desktop needs but I'm not a Linux expert.
Something like this might work:
- Intel Core i5-661 processor - 3.33GHz, 32nm, 87W
- Asus P7H55D-M EVO LGA1156 microATX Motherboard (CPU and mobo reviewed here
- Thermalright/Scythe/Noctua/Prolimatech socket 1156 CPU cooler
- 8Gb DD3 memory of your choice
- DVD burner of your choice
- SSD of whatever capacity you want with either an Intel or Indilinx controller
- 1-2 Nexus Real Silent or Scythe Slipstream 800rpm fans, with 1-2 Zalman fanmates or 5V fan adapters to control the fan speed.
As for a case and PSU combo, maybe try the Antec NSK3480 and swap the included PSU for a fanless Fortron PSU or Silverstone Nightjar PSU if you can find one, as there are vents in the top PSU part of the case that will allow the PSU to be cooler by convection.
Alternatively, you should be able to power this system off of a picoPSU - the 150W picoPSU
and 12.5A power brick
combination should be sufficient to power your system, with a few molex-to-SATA power cables.
Another case to consider, especially if you go with the picoPSU option would be the Silverstone TJ-08, so you would have a system something like this
, with a single fan.
Hope this helps!