If this were circa 2004-2005, I'm curious as to what it would have been using for a processor: Intel Atom (which had some Kernel Extensions in Leopard, enabling a generation of Dell Mini 9/10 Hackintoshes, IIRC), ARM, Core or maybe even G4?
The Intel Atom was released in 2008... and Arm wasn't powerful enough at the time. So it was either an early Pentium M or a G4. Probably a ULV-PPC G4 though as the case has no noticeable vents or fans for an Intel chip...