It is not legal to run OSX on any hardware other than the original Apple machines. Even though Macs are run of the mill Intel hardware now, They still are bound by the license agreement of Mac OS X.
The original physical hardware is your "license" to use Mac OS X.
Sure, you can "hackintosh" all day long no problems, and even XCode may work fine, But... its not legal. And if by some chance Apple finds out you have been developing and pushing apps through illegitimate environments, Well.... ya know. They have the right to pull all your apps, terminate your account, and even ban you from the ability of having another account in your name, etc...
So until Apple comes up with a Legal way to develop and share apps for iOS to the App Store through a PC with no Macintosh involved, it is illegal to do it any other way than using a real Mac, whether owned or hosted.