I just thought of something!
The Mac mini is tiny... almost tiny enough to fit in a PC's 5.25" drive bay. What if you were to take an especially large PC case and do some strategic cutting to mount a Mac mini inside? You could build a KVM switch into the case and put the KVM switch, power button, and port replicators onto another 5.25" faceplate, much like a fan control panel.
That's way out of my area of expertise, but I think it would be doable, and wouldn't it be awesome to have a PC and a Mac all built into a single box? Of course, you can accomplish almost the same thing by just duct-taping a Mac mini onto a PC case, but where's the fun in that?