Heck, until Rhapsody Developer Release 2 Apple shipped IA-32 builds. It was only after that, with Mac OS X Server 1.0 that they dropped IA-32 support publicly. That they'd kept the whole thing running on IA-32 never seemed at all far-fetched.

It also ran on SPARC and PA-RISC, I think even some Motorola 68000 at some point.

Yes, NeXT's original hardware platform was 68K based: the NeXT Cube and NeXTStation (slab.) They were 68030 and later, 68040, based machines.

I didn't mean to be didactic. I was thinking more that likely remains fairly easy to port. :-)

Oh, sorry! I have a NeXTstation in my retro collection and have a fondness for those old machines. I plan to install NeXTStep on a Sparc but haven't got there yet...

They were already working on PPC but when they went software-only the hardware division was sold to Canon and spun off as Firepower Systems.