If Microsoft made/controlled distribution of all the computer hardware in a PC and prevented anyone else from making a PC people would be mad as hell!
The latter is much much more of a grey area then the former. However, I think pystar does the former. I remember reading awhile ago that pystar shipped with a legit copy of OS X but a hacked copy installed, so if anyone wanted to reinstall, they would have to send it back and pay $50.
Hacked != Pirated.
I am planning to use a hacked MacOS X for IPhone development and I will buy the OS. That's fine, I can pay for the software.
I simply can't afford their overpriced desktop hardware. (The iPhone is reasonably cheap compared to their desktops).
Edit: I don't know why this has been down voted. Maybe I should say that what adds to Apple's desktops cost, besides their premium for the brand, is the importation tax for items over $500 here. As high as 60%. With this tax, I can simply buy the software and assembly the hardware from commodity parts myself.
Though if you're going by the "I bought a legit copy. I should be able to download it in modified forms if I want to" argument, then thats grayer then I would like. Especially if I'm developing for a platform that's controlled by the company that I'm pirating from.