I looked into this, based on my previous experience with hackintoshes. Part of the problem is that even though OSX's kernel is open-source, iOS's kernel is not. Also, OSX uses kernel extensions (kexts) to load drivers and stuff, and you could get around that by modifying/adding kexts for your non-Apple hardware. Apple needed kexts so they didn't have to release a different kernel for each and every different Mac they made, with all their various hardware differences. But iPhones are all the same. So are iPod Touches. So are all iPads. Of course, they're not ALL the same, but they have as much identical hardware as they can. This means you can't fiddle with the kext for, say, the GSM radio because it's in the closed-source kernel.

When I realized that the iPhone and iPad have same CPU architecture I also was thinking, "Yay! It's OSx86 all over again!" I mean even if I like it less than Maemo it's still cool. I would have access to more apps, I'd have more choice, I'd have more chances to annoy stupid iPhone fanboys, heck why NOT do it?

But I never even was good at hackintoshing, and the experts say it's not happening.