I've searched most of the technical docs on the Que!Fire and I can't find it's dimensions anywhere. Does it fit on top of a G3/4 case without hanging over the edges?

[Demonhood]

It fits just fine. I have mine sitting on my G4/MP right now. The fattest part of the drive extends beyond the graphite colored top of the G4 case, but since the case bulges out a bit going down to the apple logos, it works out just fine. So if you have your case wedged in a space barely big enough for it, the drive will still fit on top.