One can hope this will become eventually possible, but with the pace of PureDarwin as it is, I doubt it will before Apple migrates to ARM with custom instruction set additions.
Wouldn't you have to reverse-engineer and implement a LOT of closed-source APIs and libraries to get a full iOS toolchain going?
There is a project [1][2] to emulate iOS in QEMU. You can find more details about installation process and research itself in their articles [3][4].
Using this for that would probably break terms of service just as much as a hackintosh would.
Depends the country you are in, a lot of countries have interoperability exceptions, so while a hackintosh might not be legal, something like this would.