Wow, those towers are exactly what is needed here.
Well, you can still buy a PC with OS X on it in Germany: http://pearc.de.
German laws are different than US American laws. Microsoft learned that lesson back in the year 2000 with the so-called "OEM Urteil" when the German Bundesgerichtshof made it clear that several of Microsoft's EULA terms were illegal. This significantly changed Microsoft's business model in German and since then OEM and SystemBuilder versions can be sold and re-sold WITHOUT being bundled with a specific hardware.
Now Apple's EULA for OS X basically tries to force a bundle between their operating system and very specific hardware -- which essentially is the same what Microsoft tried to do with their OEM software license agreements.
PearC does not pre-install Apple's operating system software. They just provide the hardware and certain software that allows for booting and installing a RETAIL BOX VERSION of OS X. No copyright infringement there. No modification of Apple's software. And since German laws make certain EULA terms illegal that Apple nevertheless still have in their EULA, Apple's legal department has zero case against those guys.
On a technical note, I do not know how well those PearC machines work. I know from own experiments that OS X runs pretty well on certain Dell machines. I also know that Windows and Ubuntu Linux run very well on Apple hardware. And none of this is very surprising, because a Mac is basically just a standard, off-the-shelf Intel PC in a pretty designer case. So as long as the PC hardware resembles the hardware configuration of a Mac, there is no technical reason why OS X should not work on it.