While there are things like FlashBuilder, these solutions don't provide the performance or flexibility of an actual native application. As for virtualizing OS X, this is not an option. The EULA for all versions of OS X specifically prohibit hardware virtualization (though I believe Lion allows for it but only when running directly on genuine Apple hardware. In other words, there is no way to run OS X on any computer other than a Mac without violating the EULA.
