You can easily mod a 120x20 fan (there is a low-speed YL that meets this spec, which is silent at 5-7V) into this case by drilling four holes into the mesh top. It is just a bit shorter than your spec, but otherwise should work:
I have actually built a C2D E5200 9300-based system (Zotac) in this case. You will want to replace the stock power brick with a fanless one, although the stock DC board should be more than enough for an ION. A 90W+ Pico PSU would be needed for a "real" system.
The only caveat is whether the heatsink height on the ION board will give you enough clearance. However, even if it were taller than the HS on the Zotac C2D ITX board, you should still be able to fit one of those super-thin Scythe fans- and with its lower heat output, the ION should be just fine.