Not natively. You can install Linux (natively) tben run an x86 emulator which can then run an x86 OS... painfully slowly, and not really useable. But sure, it's "possible."
As for OS X, if there was enough demand, it really shouldn't be that difficult to get it running within a VM on Linux. You could forego the processor emulation, since the main PPU of the Cell processor is a PowerPC-based core. You would have to emulate the older PPC Mac hardware, and "fool" OS X into thinking its being installed on a native machine (as they do with other "hackintoshes"), but you're talking about hundreds or thousands of dev hours by people experienced in hacking Apple's protections, etc, and then, you'd still be emulating an old PPC Mac.
