An anonymous reader points out Gizmodo's review of a USB dongle, made by a company called Efix, which allows for an effort-free transformation of a non-Apple computer into one that runs Mac OS X. According to the reviewer, the transformation is perfect
(aside from a few quirks he describes as "trivial"); the included screenshots sure make it seem that way, too. The dongle costs $155, and works only on a subset of PC hardware. Non-Apple machines running OS X will no doubt make Apple unhappy, though, so, the reviewer concludes, "it's understandable if you wanna approach this with caution."